Maize hybrid variety X5K664

ABSTRACT

A novel hybrid maize variety designated X5K664 and seed, plants and plant parts thereof, produced by crossing Pioneer Hi-Bred International, Inc. proprietary inbred maize varieties. Methods for producing a maize plant that comprises crossing hybrid maize variety X5K664 with another maize plant. Methods for producing a maize plant containing in its genetic material one or more traits introgressed into X5K664 through backcross conversion and/or transformation, and to the maize seed, plant and plant part produced thereby. This invention relates to the maize hybrid_variety X5K664, the hybrid seed, the hybrid plant produced from the seed, and variants, mutants, and minor modifications of hybrid maize variety X5K664. This invention further relates to methods for producing maize varieties derived from hybrid maize variety X5K664 and to the maize varieties derived by the use of those methods.

FIELD OF THE INVENTION

This invention relates generally to the field of maize breeding,specifically relating to hybrid maize designated X5K664.

BACKGROUND OF THE INVENTION

The goal of hybrid development is to combine, in a single hybrid,various desirable traits. For field crops, these traits may includeresistance to diseases and insects, resistance to heat and drought,reducing the time to crop maturity, greater yield, and better agronomicquality. With mechanical harvesting of many crops, uniformity of plantcharacteristics such as germination, stand establishment, growth rate,maturity, and plant and ear height is important. Traditional plantbreeding is an important tool in developing new and improved commercialcrops.

SUMMARY OF THE INVENTION

According to the invention, there is provided a maize hybrid variety,seed, plant, and its parts designated as X5K664, produced by crossingtwo Pioneer Hi-Bred International, Inc. proprietary maize inbredvarieties. This invention relates to the maize hybrid X5K664, the hybridseed, the hybrid plant and its parts produced from the seed, andvariants, mutants and minor modifications of maize hybrid X5K664. Thisinvention also relates to processes for making a maize plant containingin its genetic material one or more traits introgressed into X5K664through backcross conversion and/or transformation, and to the maizeseed, plant and plant part produced by such introgression. Thisinvention further relates to methods for producing maize varietiesderived from hybrid maize X5K664 and to the maize varieties produced bythe use of those processes. This maize hybrid variety is characterizedby high grain yield, good dry down and strong diplodia ear rot andfusarium ear rot resistance.

DEFINITIONS

Certain definitions used in the specification are provided below. Alsoin the examples that follow, a number of terms are used herein. In orderto provide a clear and consistent understanding of the specification andclaims, including the scope to be given such terms, the followingdefinitions are provided. NOTE: ABS is in absolute terms and % MN ispercent of the mean for the experiments in which the inbred or hybridwas grown. PCT designates that the trait is calculated as a percentage.% NOT designates the percentage of plants that did not exhibit a trait.For example, STKLDG % NOT is the percentage of plants in a plot thatwere not stalk lodged. These designators will follow the descriptors todenote how the values are to be interpreted. Below are the descriptorsused in the data tables included herein.

ABIOTIC STRESS TOLERANCE. Resistance to non-biological sources of stressconferred by traits such as nitrogen utilization efficiency, alterednitrogen responsiveness, drought resistance cold, and salt resistance.

ABTSTK=ARTIFICIAL BRITTLE STALK. A count of the number of “snapped”plants per plot following machine snapping. A snapped plant has itsstalk completely snapped at a node between the base of the plant and thenode above the ear. Expressed as percent of plants that did not snap.

ADF=PERCENT ACID DETERGENT FIBER. The percent of dry matter that is aciddetergent fiber in chopped whole plant forage.

ALLELE. Any of one or more alternative forms of a genetic sequence. In adiploid cell or organism, the two alleles of a given sequence typicallyoccupy corresponding loci on a pair of homologous chromosomes.

ALTER. The utilization of up-regulation, down-regulation, or genesilencing.

ANTHESIS. The time of a flower's opening.

ANTIOXIDANT. A chemical compound or substance that inhibits oxidation,including but not limited to tocopherol or tocotrienols.

ANT ROT=ANTHRACNOSE STALK ROT (Colletotrichum graminicola). A 1 to 9visual rating indicating the resistance to Anthracnose Stalk Rot. Ahigher score indicates a higher resistance. Data are collected only whensufficient selection pressure exists in the experiment measured.

BACKCROSSING. Process in which a breeder crosses a hybrid progenyvariety back to one of the parental genotypes one or more times.

BACKCROSS PROGENY. Progeny plants produced by crossing a maize inbredparent of X5K664 plant parts with plant parts of another maize line thatcomprise a desired trait or locus, selecting F1 progeny plants thatcomprise the desired trait or locus, and crossing the selected F1progeny plants with the X5K664 plants 1 or more times to producebackcross progeny plants that comprise said trait or locus.

BARPLT=BARREN PLANTS. The percent of plants per plot that were notbarren (lack ears).

BORBMN=ARTIFICIAL BRITTLE STALK MEAN. The mean percent of plants not“snapped” in a plot following artificial selection pressure. A snappedplant has its stalk completely snapped at a node between the base of theplant and the node above the ear. Expressed as percent of plants thatdid not snap. A high number is good and indicates tolerance to brittlesnapping.

BRENGMN=BRITTLE STALK ENERGY MEAN. The mean amount of energy per unitarea needed to artificially brittle snap a corn stalk. A high number isgood and indicates tolerance to brittle snapping.

BREEDING. The genetic manipulation of living organisms.

BREEDING CROSS. A cross to introduce new genetic material into a plantfor the development of a new variety. For example, one could cross plantA with plant B, wherein plant B would be genetically different fromplant A. After the breeding cross, the resulting F1 plants could then beselfed or sibbed for one, two, three or more times (F1, F2, F3, etc.)until a new inbred variety is developed. For clarification, such newinbred variety would be within a pedigree distance of one breeding crossof plants A and B. The process described above would be referred to asone breeding cycle.

BRLPNE=ARTIFICIAL ROOT LODGING EARLY SEASON. The percent of plants notroot lodged in a plot following artificial selection pressure appliedprior to flowering. A plant is considered root lodged if it leans fromthe vertical axis at an approximately 30 degree angle or greater.Expressed as percent of plants that did not root lodge. A high number isgood and indicates tolerance to root lodging.

BRLPNL=ARTIFICIAL ROOT LODGING LATE SEASON. The percent of plants notroot lodged in a plot following artificial selection pressure duringgrain fill. A plant is considered root lodged if it leans from thevertical axis at an approximately 30 degree angle or greater. Expressedas percent of plants that did not root lodge. A high number is good andindicates tolerance to root lodging.

BRTSTK=BRITTLE STALKS. This is a measure of the stalk breakage near thetime of pollination, and is an indication of whether a hybrid or inbredwould snap or break near the time of flowering under severe winds. Dataare presented as percentage of plants that did not snap. Data arecollected only when sufficient selection pressure exists in theexperiment measured.

CARBOHYDRATE. Organic compounds comprising carbon, oxygen and hydrogen,including sugars, starches and cellulose.

CELL. Cell as used herein includes a plant cell, whether isolated, intissue culture or incorporated in a plant or plant part.

CLDTST=COLD TEST. The percent of plants that germinate under cold testconditions.

CLN=CORN LETHAL NECROSIS. Synergistic interaction of maize chloroticmottle virus (MCMV) in combination with either maize dwarf mosaic virus(MDMV-A or MDMV-B) or wheat streak mosaic virus (WSMV). A 1 to 9 visualrating indicating the resistance to Corn Lethal Necrosis. A higher scoreindicates a higher resistance. Data are collected only when sufficientselection pressure exists in the experiment measured.

COMRST=COMMON RUST ( Puccinia sorghi). A 1 to 9 visual rating indicatingthe resistance to Common Rust. A higher score indicates a higherresistance. Data are collected only when sufficient selection pressureexists in the experiment measured.

CP=PERCENT OF CRUDE PROTEIN. The percent of dry matter that is crudeprotein in chopped whole plant forage.

CROSS POLLINATION. A plant is cross pollinated if the pollen comes froma flower on a different plant from a different family or variety. Crosspollination excludes sib and self pollination.

CROSSING. The combination of genetic material by traditional methodssuch as a breeding cross or backcross, but also including protoplastfusion and other molecular biology methods of combining genetic materialfrom two sources.

CRWNIS=CORN ROOTWORM NODE INJURY SCALE (Diabrotica sp.). A 0-3 visualrating based on the proportion of roots pruned by corn rootworm larvaeto less than 1.5 inches of the crown. 0 indicates no feeding, 3indicates a total of 3 entire nodes of roots pruned.

D/D=DRYDOWN. This represents the relative rate at which a hybrid willreach acceptable harvest moisture compared to other hybrids on a 1 to 9rating scale. A high score indicates a hybrid that dries relatively fastwhile a low score indicates a hybrid that dries slowly.

DIPERS=DIPLODIA EAR MOLD SCORES (Diplodia maydis and Diplodiamacrospora). A 1 to 9 visual rating indicating the resistance toDiplodia Ear Mold. A higher score indicates a higher resistance. Dataare collected only when sufficient selection pressure exists in theexperiment measured.

DIPLOID PLANT PART. Refers to a plant part or cell that has the samediploid genotype as X5K664.

DIPROT=DIPLODIA STALK ROT SCORE. Score of stalk rot severity due toDiplodia (Diplodia maydis). Expressed as a 1 to 9 score with 9 beinghighly resistant. Data are collected only when sufficient selectionpressure exists in the experiment measured.

DM=PERCENT OF DRY MATTER. The percent of dry material in chopped wholeplant silage.

DRPEAR=DROPPED EARS. A measure of the number of dropped ears per plotand represents the percentage of plants that did not drop ears prior toharvest. Data are collected only when sufficient selection pressureexists in the experiment measured.

D/T=DROUGHT TOLERANCE. This represents a 1 to 9 rating for droughttolerance, and is based on data obtained under stress conditions. A highscore indicates good drought tolerance and a low score indicates poordrought tolerance. Data are collected only when sufficient selectionpressure exists in the experiment measured.

EARHT=EAR HEIGHT. The ear height is a measure from the ground to thehighest placed developed ear node attachment and is measured incentimeters.

EARMLD=GENERAL EAR MOLD. Visual rating (1 to 9 score) where a 1 is verysusceptible and a 9 is very resistant. This is based on overall ratingfor ear mold of mature ears without determining the specific moldorganism, and may not be predictive for a specific ear mold. Data arecollected only when sufficient selection pressure exists in theexperiment measured.

EARSZ=EAR SIZE. A 1 to 9 visual rating of ear size. The higher therating the larger the ear size.

EBTSTK=EARLY BRITTLE STALK. A count of the number of “snapped” plantsper plot following severe winds when the corn plant is experiencing veryrapid vegetative growth in the V5-V8 stage. Expressed as percent ofplants that did not snap. Data are collected only when sufficientselection pressure exists in the experiment measured.

ECB1LF=EUROPEAN CORN BORER FIRST GENERATION LEAF FEEDING (Ostrinianubilalis). A 1 to 9 visual rating indicating the resistance topreflowering leaf feeding by first generation European Corn Borer. Ahigher score indicates a higher resistance. Data are collected only whensufficient selection pressure exists in the experiment measured.

ECB2IT=EUROPEAN CORN BORER SECOND GENERATION INCHES OF TUNNELING(Ostrinia nubilalis). Average inches of tunneling per plant in thestalk. Data are collected only when sufficient selection pressure existsin the experiment measured.

ECB2SC=EUROPEAN CORN BORER SECOND GENERATION (Ostrinia nubilalis). A 1to 9 visual rating indicating post flowering degree of stalk breakageand other evidence of feeding by second generation European Corn Borer.A higher score indicates a higher resistance. Data are collected onlywhen sufficient selection pressure exists in the experiment measured.

ECBDPE=EUROPEAN CORN BORER DROPPED EARS (Ostrinia nubilalis). Droppedears due to European Corn Borer. Percentage of plants that did not dropears under second generation European Corn Borer infestation. Data arecollected only when sufficient selection pressure exists in theexperiment measured.

ECBLSI=EUROPEAN CORN BORER LATE SEASON INTACT (Ostrinia nubilalis). A 1to 9 visual rating indicating late season intactness of the corn plantgiven damage (stalk breakage above and below the top ear) causedprimarily by 2^(nd) and/or 3^(rd) generation ECB larval feeding beforeharvest. A higher score is good and indicates more intact plants. Dataare collected only when sufficient selection pressure exists in theexperiment measured.

EGRWTH=EARLY GROWTH. This is a measure of the relative height and sizeof a corn seedling at the 2-4 leaf stage of growth. This is a visualrating (1 to 9), with 1 being weak or slow growth, 5 being averagegrowth and 9 being strong growth. Taller plants, wider leaves, moregreen mass and darker color constitute a higher score. Data arecollected only when sufficient selection pressure exists in theexperiment measured.

ELITE INBRED. An inbred that contributed desirable qualities when usedto produce commercial hybrids. An elite inbred may also be used infurther breeding for the purpose of developing further improvedvarieties.

ERTLDG=EARLY ROOT LODGING. The percentage of plants that do not rootlodge prior to or around anthesis; plants that lean from the verticalaxis at an approximately 30 degree angle or greater would be counted asroot lodged. Data are collected only when sufficient selection pressureexists in the experiment measured.

ERTLPN=EARLY ROOT LODGING. An estimate of the percentage of plants thatdo not root lodge prior to or around anthesis; plants that lean from thevertical axis at an approximately 30 degree angle or greater would beconsidered as root lodged. Data are collected only when sufficientselection pressure exists in the experiment measured.

ERTLSC=EARLY ROOT LODGING SCORE. Score for severity of plants that leanfrom a vertical axis at an approximate 30 degree angle or greater whichtypically results from strong winds prior to or around floweringrecorded within 2 weeks of a wind event. Expressed as a 1 to 9 scorewith 9 being no lodging. Data are collected only when sufficientselection pressure exists in the experiment measured.

ESSENTIAL AMINO ACIDS. Amino acids that cannot be synthesized de novo byan organism and therefore must be supplied in the diet.

ESTCNT=EARLY STAND COUNT. This is a measure of the stand establishmentin the spring and represents the number of plants that emerge on a perplot basis for the inbred or hybrid.

EYESPT=EYE SPOT (Kabatiella zeae or Aureobasidium zeae). A 1 to 9 visualrating indicating the resistance to Eye Spot. A higher score indicates ahigher resistance. Data are collected only when sufficient selectionpressure exists in the experiment measured.

EXPRESSING. Having the genetic potential such that under the rightconditions, the phenotypic trait is present.

FATTY ACID. A carboxylic acid (or organic acid), often with a longaliphatic tail (long chains), either saturated or unsaturated.

F1 PROGENY. Progeny plants produced by crossing plant parts of maizevariety X5K664 with plant parts of another maize line.

FUSERS=FUSARIUM EAR ROT SCORE (Fusarium moniliforme or Fusariumsubglutinans). A 1 to 9 visual rating indicating the resistance toFusarium Ear Rot. A higher score indicates a higher resistance. Data arecollected only when sufficient selection pressure exists in theexperiment measured.

GDU=Growing Degree Units. Using the Barger Heat Unit Theory, whichassumes that maize growth occurs in the temperature range 50 degrees F.−86 degrees F. and that temperatures outside this range slow downgrowth; the maximum daily heat unit accumulation is 36 and the minimumdaily heat unit accumulation is 0. The seasonal accumulation of GDU is amajor factor in determining maturity zones.

GDUSHD=GDU TO SHED. The number of growing degree units (GDUs) or heatunits required for an inbred variety or hybrid to have approximately 50percent of the plants shedding pollen and is measured from the time ofplanting. Growing degree units are calculated by the Barger Method,where the heat units for a 24-hour period are:

${GDU} = {\frac{\left( {{Max}.\mspace{11mu}{temp}.{+ {{Min}.\mspace{11mu}{temp}.}}} \right)}{2} - 50}$

The highest maximum temperature used is 86 degrees F. and the lowestminimum temperature used is 50 degrees F. For each inbred or hybrid ittakes a certain number of GDUs to reach various stages of plantdevelopment.

GDUSLK=GDU TO SILK. The number of growing degree units required for aninbred variety or hybrid to have approximately 50 percent of the plantswith silk emergence from time of planting. Growing degree units arecalculated by the Barger Method as given in GDU SHD definition.

GENE SILENCING. The interruption or suppression of the expression of agene at the level of transcription or translation.

GENOTYPE. Refers to the genetic constitution of a cell or organism.

GIBERS=GIBBERELLA EAR ROT (PINK MOLD) (Gibberella zeae). A 1 to 9 visualrating indicating the resistance to Gibberella Ear Rot. A higher scoreindicates a higher resistance. Data are collected only when sufficientselection pressure exists in the experiment measured.

GIBROT=GIBBERELLA STALK ROT SCORE. Score of stalk rot severity due toGibberella (Gibberella zeae). Expressed as a 1 to 9 score with 9 beinghighly resistant. Data are collected only when sufficient selectionpressure exists in the experiment measured.

GLFSPT=GRAY LEAF SPOT (Cercospora zeae-maydis). A 1 to 9 visual ratingindicating the resistance to Gray Leaf Spot. A higher score indicates ahigher resistance. Data are collected only when sufficient selectionpressure exists in the experiment measured.

GOSWLT=GOSS' WILT (Corynebacterium nebraskense). A 1 to 9 visual ratingindicating the resistance to Goss' Wilt. A higher score indicates ahigher resistance. Data are collected only when sufficient selectionpressure exists in the experiment measured.

GRNAPP=GRAIN APPEARANCE. This is a 1 to 9 rating for the generalappearance of the shelled grain as it is harvested based on such factorsas the color of harvested grain, any mold on the grain, and any crackedgrain. High scores indicate good grain quality.

H/POP=YIELD AT HIGH DENSITY. Yield ability at relatively high plantdensities on a 1 to 9 relative rating system with a higher numberindicating the hybrid responds well to high plant densities for yieldrelative to other hybrids. A 1, 5, and 9 would represent very poor,average, and very good yield response, respectively, to increased plantdensity.

HAPLOID PLANT PART. Refers to a plant part or cell that has the samehaploid genotype as X5K664.

HCBLT=HELMINTHOSPORIUM CARBONUM LEAF BLIGHT (Helminthosporium carbonum).A 1 to 9 visual rating indicating the resistance to Helminthosporiuminfection. A higher score indicates a higher resistance. Data arecollected only when sufficient selection pressure exists in theexperiment measured.

HD SMT=HEAD SMUT (Sphacelotheca reiliana). This score indicates thepercentage of plants not infected. Data are collected only whensufficient selection pressure exists in the experiment measured.

HSKCVR=HUSK COVER. A 1 to 9 score based on performance relative to keychecks, with a score of 1 indicating very short husks, tip of ear andkernels showing; 5 is intermediate coverage of the ear under mostconditions, sometimes with thin husk; and a 9 has husks extending andclosed beyond the tip of the ear. Scoring can best be done nearphysiological maturity stage or any time during dry down untilharvested.

HYBRID VARIETY. A substantially heterozygous hybrid and minor geneticmodifications thereof that retain the overall genetics of the hybridincluding but not limited to a locus conversion, a mutation, or asomoclonal variant.

INBRED. A variety developed through inbreeding or doubled haploidy thatpreferably comprises homozygous alleles at about 95% or more of itsloci.

INBRED VARIETY. A substantially homozygous inbred line and minormodifications thereof that retain the overall genetics of the inbredline including but not limited to a locus conversion, a mutation, or asomoclonal variant.

INC D/A=GROSS INCOME (DOLLARS PER ACRE). Relative income per acreassuming drying costs of two cents per point above 15.5 percent harvestmoisture and current market price per bushel.

INCOME/ACRE. Income advantage of hybrid to be patented over other hybridon per acre basis.

INC ADV=GROSS INCOME ADVANTAGE. Gross income advantage of variety #1over variety #2.

INTROGRESSION. The process of transferring genetic material from onegenotype to another.

KERUNT=KERNELS PER UNIT AREA (Acres or Hectares).

KERPOP=KERNEL POP SCORE. The visual 1-9 rating of the amount ofrupturing of the kernel pericarp at an early stage in grain fill. Ahigher score is good and indicates no popped (ruptured) kernels.

KER WT=KERNEL NUMBER PER UNIT WEIGHT (Pounds or Kilograms). The numberof kernels in a specific measured weight; determined after removal ofextremely small and large kernels.

KSZDCD=KERNEL SIZE DISCARD. The percent of discard seed; calculated asthe sum of discarded tip kernels and extra large kernels.

LINKAGE. Refers to a phenomenon wherein alleles on the same chromosometend to segregate together more often than expected by chance if theirtransmission was independent.

LINKAGE DISEQUILIBRIUM. Refers to a phenomenon wherein alleles tend toremain together in linkage groups when segregating from parents tooffspring, with a greater frequency than expected from their individualfrequencies.

LOCUS. A specific location on a chromosome.

LOCUS CONVERSION. A locus conversion refers to plants within a varietythat have been modified in a manner that retains the overall genetics ofthe variety and further comprises one or more loci with a specificdesired trait, such as insect, disease or herbicide resistance.Synonymous with introgression.

L/POP=YIELD AT LOW DENSITY. Yield ability at relatively low plantdensities on a 1 to 9 relative system with a higher number indicatingthe hybrid responds well to low plant densities for yield relative toother hybrids. A 1, 5, and 9 would represent very poor, average, andvery good yield response, respectively, to low plant density.

LRTLDG=LATE ROOT LODGING. The percentage of plants that do not rootlodge after anthesis through harvest; plants that lean from the verticalaxis at an approximately 30 degree angle or greater would be counted asroot lodged. Data are collected only when sufficient selection pressureexists in the experiment measured.

LRTLPN=LATE ROOT LODGING. An estimate of the percentage of plants thatdo not root lodge after anthesis through harvest; plants that lean fromthe vertical axis at an approximately 30 degree angle or greater wouldbe considered as root lodged. Data are collected only when sufficientselection pressure exists in the experiment measured.

LRTLSC=LATE ROOT LODGING SCORE. Score for severity of plants that leanfrom a vertical axis at an approximate 30 degree angle or greater whichtypically results from strong winds after flowering. Recorded prior toharvest when a root-lodging event has occurred. This lodging results inplants that are leaned or “lodged” over at the base of the plant and donot straighten or “goose-neck” back to a vertical position. Expressed asa 1 to 9 score with 9 being no lodging. Data are collected only whensufficient selection pressure exists in the experiment measured.

MALE STERILITY. A male sterile plant is one which produces no viablepollen. Male sterility prevents self pollination and the pollination ofneighboring plants. These male sterile plants are therefore useful inhybrid plant production.

MDMCPX=MAIZE DWARF MOSAIC COMPLEX (MDMV=Maize Dwarf Mosaic Virus andMCDV=Maize Chlorotic Dwarf Virus). A 1 to 9 visual rating indicating theresistance to Maize Dwarf Mosaic Complex. A higher score indicates ahigher resistance. Data are collected only when sufficient selectionpressure exists in the experiment measured.

MST=HARVEST MOISTURE. The moisture is the actual percentage moisture ofthe grain at harvest.

MSTADV=MOISTURE ADVANTAGE. The moisture advantage of variety #1 overvariety #2 as calculated by: MOISTURE of variety #2—MOISTURE of variety#1=MOISTURE ADVANTAGE of variety #1.

NEI DISTANCE. A quantitative measure of percent similarity between twovarieties. Nei's distance between varieties A and B can be defined as1−(2*number alleles in common/(number alleles in A+number alleles in B).For example, if lines A and B are the same for 95 out of 100 alleles,the Nei distance would be 0.05. If varieties A and B are the same for 98out of 100 alleles, the Nei distance would be 0.02. Free software forcalculating Nei distance is available on the internet at multiplelocations such as, for example, at:evolution.genetics.washington.edu/phylip.html. See Nei, Proc Natl AcadSci, 76:5269-5273 (1979) which is incorporated by reference for thispurpose.

NLFBLT=NORTHERN LEAF BLIGHT (Helminthosporium turcicum or Exserohilumturcicum). A 1 to 9 visual rating indicating the resistance to NorthernLeaf Blight. A higher score indicates a higher resistance. Data arecollected only when sufficient selection pressure exists in theexperiment measured.

OILT=GRAIN OIL. Absolute value of oil content of the kernel as predictedby Near-infrared Transmittance and expressed as a percent of dry matter.

PEDIGREE DISTANCE. Relationship among generations based on theirancestral links as evidenced in pedigrees. May be measured by thedistance of the pedigree from a given starting point in the ancestry.

PERCENT IDENTITY. Percent identity as used herein refers to thecomparison of the alleles of two plants or varieties as scored bymatching loci. Percent identity is determined by comparing astatistically significant number of the loci of two plants or varietiesand scoring a match when the same two alleles are present at the sameloci for each plant. For example, a percent identity of 90% betweenhybrid maize X5K664 and another plant means that the two plants have thesame two alleles at 90% of their loci.

PERCENT SIMILARITY. Percent similarity as used herein refers to thecomparison of the alleles of two plants or varieties as scored bymatching alleles. Percent similarity is determined by comparing astatistically significant number of the loci of two plants or varietiesand scoring one allele match when the same allele is present at the sameloci for each plant and two allele matches when the same two alleles arepresent at the same loci for each plant. A percent similarity of 90%between hybrid maize X5K664 and another plant means that the two plantshave 90% matching alleles.

PLANT. As used herein, the term “plant” includes reference to animmature or mature whole plant, including a plant that has beendetasseled or from which seed or grain has been removed. Seed or embryothat will produce the plant is also considered to be the plant.

PLANT PARTS. As used herein, the term “plant parts” includes leaves,stems, roots, seed, grain, embryo, pollen, ovules, flowers, ears, cobs,husks, stalks, root tips, anthers, pericarp, silk, tissue, cells and thelike.

PLTHT=PLANT HEIGHT. This is a measure of the height of the plant fromthe ground to the tip of the tassel in centimeters.

POLPRD=POLLEN PRODUCTION SCORE. The estimated total amount of pollenproduced by tassels based on the number of tassel branches and thedensity of the spikelets.

POLSC=POLLEN SCORE. A 1 to 9 visual rating indicating the amount ofpollen shed. The higher the score the more pollen shed.

POLWT=POLLEN WEIGHT. This is calculated by dry weight of tasselscollected as shedding commences minus dry weight from similar tasselsharvested after shedding is complete.

POP K/A=PLANT POPULATIONS. Measured as 1000's per acre.

POP ADV=PLANT POPULATION ADVANTAGE. The plant population advantage ofvariety #1 over variety #2 as calculated by PLANT POPULATION of variety#2—PLANT POPULATION of variety #1=PLANT POPULATION ADVANTAGE of variety#1.

PRM=PREDICTED RELATIVE MATURITY. This trait, predicted relativematurity, is based on the harvest moisture of the grain. The relativematurity rating is based on a known set of checks and utilizes standardlinear regression analyses and is also referred to as the ComparativeRelative Maturity Rating System that is similar to the MinnesotaRelative Maturity Rating System.

PRMSHD=A relative measure of the growing degree units (GDU) required toreach 50% pollen shed. Relative values are predicted values from thelinear regression of observed GDU's on relative maturity of commercialchecks.

PROT=GRAIN PROTEIN. Absolute value of protein content of the kernel aspredicted by Near-infrared Transmittance and expressed as a percent ofdry matter.

RESISTANCE. Synonymous with tolerance. The ability of a plant towithstand exposure to an insect, disease, herbicide or other condition.A resistant plant variety will have a level of resistance higher than acomparable wild-type variety.

RTLDG=ROOT LODGING. Root lodging is the percentage of plants that do notroot lodge; plants that lean from the vertical axis at an approximately30 degree angle or greater would be counted as root lodged. Data arecollected only when sufficient selection pressure exists in theexperiment measured.

RTLADV=ROOT LODGING ADVANTAGE. The root lodging advantage of variety #1over variety #2. Data are collected only when sufficient selectionpressure exists in the experiment measured.

SCTGRN=SCATTER GRAIN. A 1 to 9 visual rating indicating the amount ofscatter grain (lack of pollination or kernel abortion) on the ear. Thehigher the score the less scatter grain.

SDGVGR=SEEDLING VIGOR. This is the visual rating (1 to 9) of the amountof vegetative growth after emergence at the seedling stage(approximately five leaves). A higher score indicates better vigor.

SEED. Fertilized and ripened ovule, consisting of the plant embryo,varying amounts of stored food material, and a protective outer seedcoat. Synonymous with grain.

SEL IND=SELECTION INDEX. The selection index gives a single measure ofthe hybrid's worth based on information for up to five traits. A maizebreeder may utilize his or her own set of traits for the selectionindex. One of the traits that is almost always included is yield. Theselection index data presented in the tables represent the mean valueaveraged across testing stations.

SIL DMP=SILAGE DRY MATTER. The percent of dry material in chopped wholeplant silage.

SELF POLLINATION. A plant is self-pollinated if pollen from one floweris transferred to the same or another flower of the same plant.

SIB POLLINATION. A plant is sib-pollinated when individuals within thesame family or variety are used for pollination.

SINGLE LOCUS CONVERSION TRAIT. A trait that can be introgressed into acorn variety through introgression and/or transformation of a singlelocus. Examples of such single locus traits include mutant genes,transgenes and native traits finely mapped to a single locus. One ormore single locus conversion traits may be introduced into a single cornvariety.

SITE SPECIFIC INTEGRATION. Genes that create a site for site specificDNA integration. This includes the introduction of FRT sites that may beused in the FLP/FRT system and/or Lox sites that may be used in theCre/Loxp system. For example, see Lyznik, et al., Site-SpecificRecombination for Genetic Engineering in Plants, Plant Cell Rep (2003)21:925-932 and WO 99/25821.

SLFBLT=SOUTHERN LEAF BLIGHT (Helminthosporium maydis or Bipolarismaydis). A 1 to 9 visual rating indicating the resistance to SouthernLeaf Blight. A higher score indicates a higher resistance. Data arecollected only when sufficient selection pressure exists in theexperiment measured.

SOURST=SOUTHERN RUST (Puccinia polysora). A 1 to 9 visual ratingindicating the resistance to Southern Rust. A higher score indicates ahigher resistance. Data are collected only when sufficient selectionpressure exists in the experiment measured.

SPKDSC=SPIKLET DENSITY SCORE. The visual 1-9 rating of how densespikelets are on the middle tassel branches. A higher score indicateshigher spikelet density.

STAGRN=STAY GREEN. Stay green is the measure of plant health near thetime of black layer formation (physiological maturity). A high scoreindicates better late-season plant health.

STARCH=PERCENT OF STARCH. The percent of dry matter that is starch inchopped whole plant forage.

STDADV=STALK STANDING ADVANTAGE. The advantage of variety #1 overvariety #2 for the trait STK CNT.

STKCNT=NUMBER OF PLANTS. This is the final stand or number of plants perplot.

STKLDG=STALK LODGING REGULAR. This is the percentage of plants that didnot stalk lodge (stalk breakage) at regular harvest (when grain moistureis between about 20 and 30%) as measured by either natural lodging orpushing the stalks and determining the percentage of plants that breakbelow the ear. Data are collected only when sufficient selectionpressure exists in the experiment measured.

STKLDS=STALK LODGING SCORE. A plant is considered as stalk lodged if thestalk is broken or crimped between the ear and the ground. This can becaused by any or a combination of the following: strong winds late inthe season, disease pressure within the stalks, ECB damage orgenetically weak stalks. This trait should be taken just prior to or atharvest. Expressed on a 1 to 9 scale with 9 being no lodging. Data arecollected only when sufficient selection pressure exists in theexperiment measured.

STLLPN=LATE STALK LODGING. This is the percent of plants that did notstalk lodge (stalk breakage or crimping) at or around late seasonharvest (when grain moisture is below 20%) as measured by either naturallodging or pushing the stalks and determining the percentage of plantsthat break or crimp below the ear. Data are collected only whensufficient selection pressure exists in the experiment measured.

STLPCN=STALK LODGING REGULAR. This is an estimate of the percentage ofplants that did not stalk lodge (stalk breakage) at regular harvest(when grain moisture is between about 20 and 30%) as measured by eithernatural lodging or pushing the stalks and determining the percentage ofplants that break below the ear. Data are collected only when sufficientselection pressure exists in the experiment measured.

STLTIP=STERILE TIPS SCORE. The visual 1 to 9 rating of the relative lackof glumes on the tassel central spike and branches. A higher scoreindicates less incidence of sterile tips or lack of glumes on thetassel.

STRT=GRAIN STARCH. Absolute value of starch content of the kernel aspredicted by Near-infrared Transmittance and expressed as a percent ofdry matter.

STWWLT=Stewart's Wilt (Erwinia stewartii). A 1 to 9 visual ratingindicating the resistance to Stewart's Wilt. A higher score indicates ahigher resistance. Data are collected only when sufficient selectionpressure exists in the experiment measured.

SSRs. Genetic markers based on polymorphisms in repeated nucleotidesequences, such as microsatellites. A marker system based on SSRs can behighly informative in linkage analysis relative to other marker systemsin that multiple alleles may be present.

TASBLS=TASSEL BLAST. A 1 to 9 visual rating was used to measure thedegree of blasting (necrosis due to heat stress) of the tassel at thetime of flowering. A 1 would indicate a very high level of blasting attime of flowering, while a 9 would have no tassel blasting. Data arecollected only when sufficient selection pressure exists in theexperiment measured.

TASBRN=TASSEL BRANCH NUMBER. The number of tassel branches, with anthersoriginating from the central spike.

TASSZ=TASSEL SIZE. A 1 to 9 visual rating was used to indicate therelative size of the tassel. The higher the rating the larger thetassel.

TAS WT=TASSEL WEIGHT. This is the average weight of a tassel (grams)just prior to pollen shed.

TDM/HA=TOTAL DRY MATTER PER HECTARE. Yield of total dry plant materialin metric tons per hectare.

TEXEAR=EAR TEXTURE. A 1 to 9 visual rating was used to indicate therelative hardness (smoothness of crown) of mature grain. A 1 would bevery soft (extreme dent) while a 9 would be very hard (flinty or verysmooth crown).

TILLER=TILLERS. A count of the number of tillers per plot that couldpossibly shed pollen was taken. Data are given as a percentage oftillers: number of tillers per plot divided by number of plants perplot.

TST WT=TEST WEIGHT (UNADJUSTED). The measure of the weight of the grainin kilograms for a given volume (cubic meter).

TSWADV=TEST WEIGHT ADVANTAGE. The test weight advantage of variety #1over variety #2.

WIN M %=PERCENT MOISTURE WINS.

WIN Y %=PERCENT YIELD WINS.

YIELD BU/A=YIELD (BUSHELS/ACRE). Yield of the grain at harvest inbushels per acre adjusted to 15% moisture.

YLDADV=YIELD ADVANTAGE. The yield advantage of variety #1 over variety#2 as calculated by: YIELD of variety #1—YIELD variety #2=YIELDADVANTAGE of variety #1.

YLDSC=YIELD SCORE. A 1 to 9 visual rating was used to give a relativerating for yield based on plot ear piles. The higher the rating thegreater visual yield appearance.

Definitions for Area of Adaptability

When referring to area of adaptability, such term is used to describethe location with the environmental conditions that would be well suitedfor this maize variety. Area of adaptability is based on a number offactors, for example: days to maturity, insect resistance, diseaseresistance, and drought resistance. Area of adaptability does notindicate that the maize variety will grow in every location within thearea of adaptability or that it will not grow outside the area.

-   Central Corn Belt: Iowa, Illinois, Indiana-   Drylands: non-irrigated areas of North Dakota, South Dakota,    Nebraska, Kansas, Colorado and Oklahoma-   Eastern U.S.: Ohio, Pennsylvania, Delaware, Maryland, Virginia, and    West Virginia North central U.S.: Minnesota and Wisconsin-   Northeast: Michigan, New York, Vermont, and Ontario and Quebec    Canada-   Northwest U.S.: North Dakota, South Dakota, Wyoming, Washington,    Oregon, Montana, Utah, and Idaho-   South central U.S.: Missouri, Tennessee, Kentucky, Arkansas-   Southeast U.S.: North Carolina, South Carolina, Georgia, Florida,    Alabama, Mississippi, and Louisiana-   Southwest U.S.: Texas, Oklahoma, New Mexico, Arizona-   Western U.S.: Nebraska, Kansas, Colorado, and California-   Maritime Europe: Northern France, Germany, Belgium, Netherlands and    Austria

DETAILED DESCRIPTION OF THE INVENTION AND FURTHER EMBODIMENTS

All tables discussed in the Detailed Description of the Invention andFurther Embodiments section can be found at the end of the section.

Field crops are bred through techniques that take advantage of theplant's method of pollination. A plant is self-pollinated if pollen fromone flower is transferred to the same or another flower of the sameplant. A plant is sib pollinated when individuals within the same familyor line are used for pollination. A plant is cross-pollinated if thepollen comes from a flower on a different plant from a different familyor line.

Plants that have been self-pollinated and selected for type for manygenerations become homozygous at almost all gene loci and produce auniform population of true breeding progeny. A cross between twodifferent homozygous lines produces a uniform population of hybridplants that may be heterozygous for many gene loci. A cross of twoplants each heterozygous at a number of gene loci will produce apopulation of heterogeneous plants that differ genetically and will notbe uniform.

Maize (Zea mays L.), often referred to as corn in the United States, canbe bred by both self-pollination and cross-pollination techniques. Maizehas separate male and female flowers on the same plant, located on thetassel and the ear, respectively. Natural pollination occurs in maizewhen wind blows pollen from the tassels to the silks that protrude fromthe tops of the ears.

There are many important factors to be considered in the art of plantbreeding, such as the ability to recognize important morphological andphysiological characteristics, the ability to design evaluationtechniques for genotypic and phenotypic traits of interest, and theability to search out and exploit the genes for the desired traits innew or improved combinations.

The objective of commercial maize hybrid variety development resultingfrom a maize plant breeding program is to develop new inbred varietiesto produce hybrids that combine to produce high grain yields andsuperior agronomic performance. Thus, maize hybrids need to be highlyhomogeneous, heterozygous and reproducible to be useful as commercialhybrids. One of the primary traits breeders seek is yield. However, manyother major agronomic traits are of importance in hybrid combination andhave an impact on yield or otherwise provide superior performance inhybrid combinations. Such traits include percent grain moisture atharvest, relative maturity, resistance to stalk breakage, resistance toroot lodging, grain quality, and disease and insect resistance.

The utility of hybrid maize variety X5K664 also extends to crosses withother species. Commonly, suitable species will be of the familyGraminaceae, and especially of the genera Zea, Tripsacum, Coix,Schlerachne, Polytoca, Chionachne, and Trilobachne, of the tribeMaydeae. Potentially suitable for crosses with X5K664 may be the variousvarieties of grain sorghum, Sorghum bicolor (L.) Moench.

Morphological and Physiological Characteristics of X5K664

Pioneer Brand Hybrid X5K664 is characterized by excellent yield andagronomics and high test weight. The hybrid is of moderate stature andexhibits solid roots and stalks. In addition it is strong for diplodiaear rot and fusarium ear rot. The hybrid is particularly suited to theCentral Corn Belt, Northcentral U.S., Northeast, and Eastern UnitedStates.

Pioneer Brand Hybrid Maize Variety X5K664 is a single cross, yellowendosperm maize hybrid. Hybrid Maize Variety X5K664 has a relativematurity of approximately 106 based on the Comparative Relative MaturityRating System for harvest moisture of grain.

The hybrid has shown uniformity and stability within the limits ofenvironmental influence for all the traits as described in the VarietyDescription Information (Table 1, found at the end of the section). Theinbred parents of this hybrid have been self-pollinated and ear-rowed asufficient number of generations with careful attention paid touniformity of plant type to ensure the homozygosity and phenotypicstability necessary for use in commercial hybrid seed production. Thevariety has been increased both by hand and in isolated fields withcontinued observation for uniformity. No variant traits have beenobserved or are expected in X5K664.

Hybrid maize variety X5K664 can be reproduced by planting seeds of theinbred parent varieties, growing the resulting maize plants under crosspollinating conditions, and harvesting the resulting seed usingtechniques familiar to the agricultural arts.

Genotypic Characteristics of X5K664

In addition to phenotypic observations, a plant can also be described byits genotype. The genotype of a plant can be characterized through agenetic marker profile which can identify plants of the same variety ora related variety or be used to determine or validate a pedigree. Forexample, the genotype can be used to determine the pedigree of a plant.There are many laboratory-based techniques available for the analysis,comparison and characterization of plant genotype; among these areIsozyme Electrophoresis, Restriction Fragment Length Polymorphisms(RFLPs), Randomly Amplified Polymorphic DNAs (RAPDs), Arbitrarily PrimedPolymerase Chain Reaction (AP-PCR), DNA Amplification Fingerprinting(DAF), Sequence Characterized Amplified Regions (SCARs), AmplifiedFragment Length Polymorphisms (AFLPs), Simple Sequence Repeats (SSRs)which are also referred to as Microsatellites, and Single NucleotidePolymorphisms (SNPs). For example, see Berry, Don, et al., “AssessingProbability of Ancestry Using Simple Sequence Repeat Profiles:Applications to Maize Hybrids and Inbreds”, Genetics, 2002, 161:813-824, and Berry, Don et al., “Assessing Probability of Ancestry UsingSimple Sequence Repeat Profiles: Applications to Maize Inbred Lines andSoybean Varieties”, Genetics, 2003, 165: 331-342, which are incorporatedby reference herein in their entirety.

Particular markers used for these purposes may include any type ofmarker and marker profile which provides a means of distinguishingvarieties. In addition to being used for identification of inbredparents, hybrid variety X5K664, a hybrid produced through the use ofX5K664 or its parents, and the identification or verification ofpedigree for progeny plants produced through the use of X5K664, thegenetic marker profile is also useful in developing an introgressedtrait conversion of X5K664.

Means of performing genetic marker profiles using SSR polymorphisms arewell known in the art. SSRs are genetic markers based on polymorphismsin repeated nucleotide sequences, such as microsatellites. A markersystem based on SSRs can be highly informative in linkage analysisrelative to other marker systems in that multiple alleles may bepresent. Another advantage of this type of marker is that, through useof flanking primers, detection of SSRs can be achieved, for example, bythe polymerase chain reaction (PCR), thereby eliminating the need forlabor-intensive Southern hybridization. The PCR™ detection is done byuse of two oligonucleotide primers flanking the polymorphic segment ofrepetitive DNA. Repeated cycles of heat denaturation of the DNA followedby annealing of the primers to their complementary sequences at lowtemperatures, and extension of the annealed primers with DNA polymerase,comprise the major part of the methodology.

Following amplification, markers can be scored by gel electrophoresis ofthe amplification products. Scoring of marker genotype is based on thesize of the amplified fragment, which may be measured by the base pairweight or molecular weight of the fragment. While variation in theprimer used or in laboratory procedures can affect the reportedmolecular weight, relative values should remain constant regardless ofthe specific primer or laboratory used. When comparing plants it ispreferable if all SSR profiles are performed in the same lab. An SSRservice is available to the public on a contractual basis by DNALandmarks in Saint-Jean-sur-Richelieu, Quebec, Canada.

Primers used for SSRs are publicly available and may be found in theMaize GDB on the World Wide Web at maizegdb.org (sponsored by the USDAAgricultural Research Service), in Sharopova et al. (Plant Mol. Biol.48(5-6):463-481), Lee et al. (Plant Mol. Biol. 48(5-6); 453-461).Primers may be constructed from publicly available sequence information.Some marker information may be available from DNA Landmarks.

The scope of the invention includes use of methods, for example, IsozymeElectrophoresis, Restriction Fragment Length Polymorphisms (RFLPs),Randomly Amplified Polymorphic DNAs (RAPDs), Arbitrarily PrimedPolymerase Chain Reaction (AP-PCR), DNA Amplification Fingerprinting(DAF), Sequence Characterized Amplified Regions (SCARs), AmplifiedFragment Length Polymorphisms (AFLPs), Simple Sequence Repeats (SSRs),and Single Nucleotide Polymorphisms (SNPs), with transgenic or backcrossconversions of maize hybrid variety X5K664. One such embodiment is amethod of developing a variety genetically similar to hybrid maizevariety X5K664 in breeding that involves the repeated backcrossing of aninbred parent of, or a double haploid inbred variety derived from,hybrid maize variety X5K664.

Comparisons for Pioneer Hybrid Maize X5K664

A breeder uses various methods to help determine which plants should beselected from segregating populations and ultimately which inbredvarieties will be used to develop hybrids for commercialization. Inaddition to knowledge of the germplasm and plant genetics, a part of theselection process is dependent on experimental design coupled with theuse of statistical analysis. Experimental design and statisticalanalysis are used to help determine which plants, which family ofplants, and finally which inbred varieties and hybrid combinations aresignificantly better or different for one or more traits of interest.Experimental design methods are used to assess error so that differencesbetween two inbred varieties or two hybrid varieties can be moreaccurately evaluated. Statistical analysis includes the calculation ofmean values, determination of the statistical significance of thesources of variation, and the calculation of the appropriate variancecomponents. One of ordinary skill in the art of plant breeding wouldknow how to evaluate the traits of two plant varieties to determine ifthere is no significant difference between the two traits expressed bythose varieties. For example, see Fehr, Walt, Principles of CultivarDevelopment, pages 261-286 (1987). Mean trait values may be used todetermine whether trait differences are significant. Trait values shouldpreferably be measured on plants grown under the same environmentalconditions, and environmental conditions should be appropriate for thetraits or traits being evaluated. Sufficient selection pressure shouldbe present for optimum measurement of traits of interest such asherbicide, insect or disease resistance. A locus conversion of X5K664for herbicide resistance should be compared with an isogenic counterpartin the absence of the converted trait. In addition, a locus conversionfor insect or disease resistance should be compared to the isogeniccounterpart, in the absence of disease pressure or insect pressure.

In Table 2 (Table 2, found at the end of the section), data from traitsand characteristics of hybrid maize X5K664 per se are given and comparedto other maize hybrid. The following are the results of thesecomparisons. The results in Table 2 show hybrid maize variety X5K664 hassignificantly different traits compared to other maize hybrid varieties.

Comparisons of characteristics for Pioneer Brand Hybrid Maize X5K664were made against Hybrid 35D28 and 35Y33.

Table 2A compares Pioneer Brand Hybrid Maize X5K664 and Hybrid 35D28, ahybrid with a similar area of adaptation. The results show Hybrid MaizeX5K664 has significantly different yield, resistance to Fusarium andtest weight when compared to Hybrid 35D28.

Table 2B compares Pioneer Brand Hybrid Maize X5K664 and Hybrid 35Y33, ahybrid with a similar area of adaptation. The results show Hybrid MaizeX5K664 differs significantly over multiple traits including yield andplant height when compared to Hybrid 35Y33.

Development of Maize Hybrids using X5K664

During the inbreeding process in maize, the vigor of the varietiesdecreases. However, vigor is restored when two different inbredvarieties are crossed to produce the hybrid progeny (F1). An importantconsequence of the homozygosity and homogeneity of the inbred varietiesis that the hybrid between a defined pair of inbreds may be reproducedindefinitely as long as the homogeneity of the inbred parents ismaintained. Once the inbreds that create a superior hybrid have beenidentified, a continual supply of the hybrid seed can be produced usingthese inbred parents and the hybrid corn plants can then be generatedfrom this hybrid seed supply.

The development of a maize hybrid in a maize plant breeding programinvolves three steps: (1) the selection of plants from various germplasmpools for initial breeding crosses; (2) the selfing of the selectedplants from the breeding crosses for several generations to produce aseries of inbred varieties, which, individually breed true and arehighly uniform; and (3) crossing a selected inbred variety with anunrelated inbred variety to produce the hybrid progeny (F1). After asufficient amount of inbreeding successive filial generations willmerely serve to increase seed of the developed inbred.

X5K664 may be used to produce a double cross hybrid or a three-wayhybrid. A single cross hybrid is produced when two inbred varieties arecrossed to produce the F1 progeny. A double cross hybrid is producedfrom four inbred varieties crossed in pairs (A×B and C×D) and then thetwo F1 hybrids are crossed again (A×B)×(C×D). A three-way cross hybridis produced from three inbred varieties where two of the inbredvarieties are crossed (A×B) and then the resulting F1 hybrid is crossedwith the third inbred variety (A×B)×C. In each case, pericarp tissuefrom the female parent will be a part of and protect the hybrid seed.

Hybrid seed production requires elimination or inactivation of pollenproduced by the female parent. Incomplete removal or inactivation of thepollen provides the potential for self-pollination. This inadvertentlyself-pollinated seed may be unintentionally harvested and packaged withhybrid seed. Also, because the male parent plant is grown in rows, thatare typically destroyed prior to seed development, next to the femaleparent in the field there is the very low probability that the maleselfed seed could be unintentionally harvested and packaged with thehybrid seed. Once the seed from the hybrid bag is planted, it ispossible to identify and select these self-pollinated plants. Theseself-pollinated plants will be one of the inbred varieties or F1's usedto produce the hybrid. Though the possibility of selfs being included ina hybrid seed bag exists, the occurrence is very low because much careis taken by seed companies to avoid such inclusions. It is worth notingthat hybrid seed is sold to growers for the production of grain andforage and not for breeding or seed production. By an individual skilledin plant breeding, these selfed plants unintentionally included incommercial hybrid seed can be identified and selected. Inbreds areidentified by their less vigorous appearance for vegetative and/orreproductive characteristics, including shorter plant height, small earsize, ear and kernel shape, cob color, or other characteristics.

Identification of these self-pollinated varieties can also beaccomplished through molecular marker analyses. See “The Identificationof Female Selfs in Hybrid Maize: A Comparison Using Electrophoresis andMorphology”, Smith, J. S. C. and Wych, R. D., Seed Science andTechnology 14, pages 1-8 (1995), the disclosure of which is expresslyincorporated herein by reference. Through these technologies, thehomozygosity of the self pollinated variety can be verified by analyzingallelic composition at various loci along the genome. Those methodsallow for rapid identification of the invention disclosed herein. Seealso, “Identification of Atypical Plants in Hybrid Maize Seed byPostcontrol and Electrophoresis” Sarca, V. et al., Probleme de GeneticaTeoritica si Aplicata Vol. 20 (1) pages 29-42.

Another form of commercial hybrid production involves the use of amixture of male sterile hybrid seed and male pollinator seed. Whenplanted, the resulting male sterile hybrid plants are pollinated by thepollinator plants. This method is primarily used to produce grain withenhanced quality grain traits, such as high oil, because desired qualitygrain traits expressed in the pollinator will also be expressed in thegrain produced on the male sterile hybrid plant. In this method thedesired quality grain trait does not have to be incorporated by lengthyprocedures such as recurrent backcross selection into an inbred parentline. One use of this method is described in U.S. Pat. Nos. 5,704,160and 5,706,603.

Introgression of a New Locus or Trait into X5K664

X5K664 represents a new base genetic line into which a new locus ortrait may be introduced. Direct transformation and backcrossingrepresent two important methods that can be used to accomplish such anintrogression. The term locus conversion is used to designate theproduct of such an introgression.

To select and develop a superior hybrid, it is necessary to identify andselect genetically unique individuals that occur in a segregatingpopulation. The segregating population is the result of a combination ofcrossover events plus the independent assortment of specificcombinations of alleles at many gene loci that results in specific andunique genotypes. Once such a variety is developed its value to societyis substantial since it is important to advance the germplasm base as awhole in order to maintain or improve traits such as yield, diseaseresistance, pest resistance and plant performance in extreme weatherconditions. Backcross trait conversions are routinely used to add ormodify one or a few traits of such a line and this further enhances itsvalue and usefulness to society. The genetic variation among individualprogeny of a breeding cross allows for the identification of rare andvaluable new genotypes. Once identified, it is possible to utilizeroutine and predictable breeding methods to develop progeny that retainthe rare and valuable new genotypes developed by the initial breeder.

Backcrossing can be used to improve inbred varieties and a hybrid whichis made using those inbreds. Backcrossing can be used to transfer aspecific desirable trait from one variety, the donor parent, to aninbred called the recurrent parent which has overall good agronomiccharacteristics yet that lacks the desirable trait. This transfer of thedesirable trait into an inbred with overall good agronomiccharacteristics can be accomplished by first crossing a recurrent parentto a donor parent (non-recurrent parent). The progeny of this cross isthen mated back to the recurrent parent followed by selection in theresultant progeny for the desired trait to be transferred from thenon-recurrent parent. Typically after four or more backcross generationswith selection for the desired trait, the progeny will containessentially all genes of the recurrent parent except for the genescontrolling the desired trait. But the number of backcross generationscan be less if molecular markers are used during the selection or elitegermplasm is used as the donor parent. The last backcross generation isthen selfed to give pure breeding progeny for the gene(s) beingtransferred.

Traits may be used by those of ordinary skill in the art to characterizeprogeny. Traits are commonly evaluated at a significance level, such asa 1%, 5% or 10% significance level, when measured in plants grown in thesame environmental conditions. For example, a backcross conversion ofX5K664 may be characterized as having the same morphological andphysiological traits as X5K664. The traits used for comparison may bethose traits shown in Table 1 or Table 2. Molecular markers can also beused during the breeding process for the selection of qualitativetraits. For example, markers closely linked to alleles or markerscontaining sequences within the actual alleles of interest can be usedto select plants that contain the alleles of interest during abackcrossing breeding program. The markers can also be used to selectfor the genome of the recurrent parent and against the genome of thedonor parent. Using this procedure can minimize the amount of genomefrom the donor parent that remains in the selected plants.

A locus conversion of X5K664 will retain the genetic integrity ofX5K664. A locus conversion of X5K664 will comprise at least 92%, 93%,94%, 95%, 96%, 97%, 98% or 99% of the base genetics of X5K664. Forexample, a locus conversion of X5K664 can be developed when DNAsequences are introduced through backcrossing (Hallauer et al., 1988),with a parent of X5K664 utilized as the recurrent parent. Both naturallyoccurring and transgenic DNA sequences may be introduced throughbackcrossing techniques. A backcross conversion may produce a plant witha trait or locus conversion in at least one or more backcrosses,including at least 2 crosses, at least 3 crosses, at least 4 crosses, atleast 5 crosses and the like. Molecular marker assisted breeding orselection may be utilized to reduce the number of backcrosses necessaryto achieve the backcross conversion. For example, see Openshaw, S. J. etal., Marker-assisted Selection in Backcross Breeding. In: ProceedingsSymposium of the Analysis of Molecular Data, August 1994, Crop ScienceSociety of America, Corvallis, Oreg., where it is demonstrated that abackcross conversion can be made in as few as two backcrosses.

The complexity of the backcross conversion method depends on the type oftrait being transferred (single genes or closely linked genes as vs.unlinked genes), the level of expression of the trait, the type ofinheritance (cytoplasmic or nuclear) and the types of parents includedin the cross. It is understood by those of ordinary skill in the artthat for single gene traits that are relatively easy to classify, thebackcross method is effective and relatively easy to manage. (SeeHallauer et al. in Corn and Corn Improvement, Sprague and Dudley, ThirdEd. 1998). Desired traits that may be transferred through single locustrait conversion include, but are not limited to, waxy starch, sterility(nuclear and cytoplasmic), fertility restoration, grain color (white),drought resistance enhanced nitrogen utilization efficiency, alterednitrogen responsiveness, altered fatty acid profile, disease resistance(bacterial, fungal or viral), insect resistance, herbicide resistanceand yield enhancements. In addition, an introgression site itself, suchas an FRT site, Lox site or other site specific integration site, may beinserted by backcrossing and utilized for direct insertion of one ormore genes of interest into a specific plant variety. The trait ofinterest is transferred from the donor parent to the recurrent parent,in this case, an inbred parent of the maize variety disclosed herein. Insome embodiments of the invention, the number of loci that may bebackcrossed into X5K664 is at least 1, 2, 3, 4, or 5 and/or no more than10, 9, 8, 7, 6, 5, 4, 3, or 2. The seed industry commonly markets“triple stacks” of base genetics; which can be varieties comprising alocus conversion of at least 3 loci. Similarly, “quadruple stacks” wouldcomprise the base genetics and could comprise a locus conversion of atleast 4 loci. The seed industry commonly markets “triple stacks” of basegenetics; which can be varieties comprising a locus conversion of atleast 3 loci. Similarly, “quadruple stacks” would comprise the basegenetics and could comprise a locus conversion of at least 4 loci.Stacking of traits is common to those of ordinary skill in the art ofplant breeding and stacked traits account for a significant percentageof commercial corn hybrid sales. For example, figures from PurdueUniversity show that biotech-trait corn accounted for 61% of all cornacres in 2006 and corn with two or more stacked traits accounted for11.9 million acres. That's a significant portion of the approximately 80million acres of corn grown in the United States. In addition, for 2007at least one company projects selling more triple-stack corn hybridsthan single trait hybrids. (Wayne Wenzel, “Double, Triple, Quad”,published Nov. 8, 2006, Agweb.com, accessed Dec. 4, 2006). A singlelocus may contain several transgenes, such as a transgene for diseaseresistance that, in the same expression vector, also contains atransgene for herbicide resistance. The gene for herbicide resistancemay be used as a selectable marker and/or as a phenotypic trait. A locustrait conversion of a site specific integration system allows for theintegration of multiple genes at the converted loci. Further, SSI andFRT technologies known to those of skill in the art in the art mayresult in multiple gene introgressions at a single locus.

The locus conversion may result from either the transfer of a dominantallele or a recessive allele. Selection of progeny containing the traitof interest is accomplished by direct selection for a trait associatedwith a dominant allele. Transgenes transferred via backcrossingtypically function as a dominant single gene trait and are relativelyeasy to classify. Selection of progeny for a trait that is transferredvia a recessive allele, such as the waxy starch characteristic, requiresgrowing and selfing the first backcross generation to determine whichplants carry the recessive alleles. Recessive traits may requireadditional progeny testing in successive backcross generations todetermine the presence of the locus of interest. The last backcrossgeneration is usually selfed to give pure breeding progeny for thegene(s) being transferred, although a backcross conversion with a stablyintrogressed trait may also be maintained by further backcrossing to therecurrent parent with selection for the converted trait.

Along with selection for the trait of interest, progeny are selected forthe phenotype and/or genotype of the recurrent parent. Whileoccasionally additional polynucleotide sequences or genes may betransferred along with the backcross conversion, the backcrossconversion variety “fits into the same hybrid combination as therecurrent parent inbred variety and contributes the effect of theadditional gene added through the backcross.” See Poehlman et al. (1995,page 334). It has been proposed that in general there should be at leastfour backcrosses when it is important that the recovered varieties beessentially identical to the recurrent parent except for thecharacteristic being transferred (Fehr 1987, Principles of CultivarDevelopment). However, as noted above, the number of backcrossesnecessary can be reduced with the use of molecular markers. Otherfactors, such as a genetically similar donor parent, may also reduce thenumber of backcrosses necessary.

Male Sterility and Hybrid Seed Production

Hybrid seed production requires elimination or inactivation of pollenproduced by the female inbred parent. Incomplete removal or inactivationof the pollen provides the potential for self-pollination. A reliablemethod of controlling male fertility in plants offers the opportunityfor improved seed production. There are several ways in which a maizeplant can be manipulated so that it is male sterile. These include useof manual or mechanical emasculation (or detasseling), use of one ormore genetic factors that confer male sterility, including cytoplasmicgenetic and/or nuclear genetic male sterility, use of gametocides andthe like. All of such embodiments are within the scope of the presentclaims. The term manipulated to be male sterile refers to the use of anyavailable techniques to produce a male sterile version of maize varietyX5K664. The male sterility may be either partial or complete malesterility.

Hybrid maize seed is often produced by a male sterility systemincorporating manual or mechanical detasseling. Alternate strips of twoinbred varieties of maize are planted in a field, and the pollen-bearingtassels are removed from one of the inbreds (female) prior to pollenshed. Providing that there is sufficient isolation from sources offoreign maize pollen, the ears of the detasseled inbred will befertilized only from the other inbred (male), and the resulting seed istherefore hybrid and will form hybrid plants.

Large scale commercial maize hybrid production, as it is practicedtoday, requires the use of some form of male sterility system whichcontrols or inactivates male fertility. A reliable method of controllingmale fertility in plants also offers the opportunity for improved plantbreeding. This is especially true for development of maize hybrids,which relies upon some sort of male sterility system. There are severalways in which a maize plant can be manipulated so that is male sterile.These include use of manual or mechanical emasculation (or detasseling),cytoplasmic genetic male sterility, nuclear genetic male sterility,gametocides and the like.

The laborious detasseling process can be avoided by using cytoplasmicmale-sterile (CMS) inbreds. Plants of a CMS inbred are male sterile as aresult of genetic factors in the cytoplasm, as opposed to the nucleus,and so nuclear linked genes are not transferred during backcrossing.Thus, this characteristic is inherited exclusively through the femaleparent in maize plants, since only the female provides cytoplasm to thefertilized seed. CMS plants are fertilized with pollen from anotherinbred that is not male-sterile. Pollen from the second inbred may ormay not contribute genes that make the hybrid plants male-fertile, andeither option may be preferred depending on the intended use of thehybrid. The same hybrid seed, a portion produced from detasseled fertilemaize and a portion produced using the CMS system can be blended toinsure that adequate pollen loads are available for fertilization whenthe hybrid plants are grown. CMS systems have been successfully usedsince the 1950's, and the male sterility trait is routinely backcrossedinto inbred varieties. See Wych, p. 585-586, 1998.

There are several methods of conferring genetic male sterilityavailable, such as multiple mutant genes at separate locations withinthe genome that confer male sterility, as disclosed in U.S. Pat. Nos.4,654,465 and 4,727,219 to Brar et al. and chromosomal translocations asdescribed by Patterson in U.S. Pat. Nos. 3,861,709 and 3,710,511. Theseand all patents referred to are incorporated by reference. In additionto these methods, Albertsen et al., of Pioneer Hi-Bred, U.S. Pat. No.5,432,068, describe a system of nuclear male sterility which includes:identifying a gene which is critical to male fertility; silencing thisnative gene which is critical to male fertility; removing the nativepromoter from the essential male fertility gene and replacing it with aninducible promoter; inserting this genetically engineered gene back intothe plant; and thus creating a plant that is male sterile because theinducible promoter is not “on” resulting in the male fertility gene notbeing transcribed. Fertility is restored by inducing, or turning “on”,the promoter, which in turn allows the gene that confers male fertilityto be transcribed.

These, and the other methods of conferring genetic male sterility in theart, each possess their own benefits and drawbacks. Some other methodsuse a variety of approaches such as delivering into the plant a geneencoding a cytotoxic substance associated with a male tissue specificpromoter or an antisense system in which a gene critical to fertility isidentified and an antisense to that gene is inserted in the plant (seeFabinjanski, et al. EPO 89/3010153.8 Publication No. 329,308 and PCTApplication PCT/CA90/00037 published as WO 90/08828).

Another system useful in controlling male sterility makes use ofgametocides. Gametocides are not a genetic system, but rather a topicalapplication of chemicals. These chemicals affect cells that are criticalto male fertility. The application of these chemicals affects fertilityin the plants only for the growing season in which the gametocide isapplied (see Carlson, Glenn R., U.S. Pat. No. 4,936,904). Application ofthe gametocide, timing of the application and genotype specificity oftenlimit the usefulness of the approach and it is not appropriate in allsituations.

Transformation

The advent of new molecular biological techniques has allowed theisolation and characterization of genetic elements with specificfunctions, such as encoding specific protein products. Scientists in thefield of plant biology developed a strong interest in engineering thegenome of plants to contain and express foreign genetic elements, oradditional, or modified versions of native or endogenous geneticelements in order to alter the traits of a plant in a specific manner.Any DNA sequences, whether from a different species or from the samespecies, which are inserted into the genome using transformation arereferred to herein collectively as “transgenes”. In some embodiments ofthe invention, a transformed variant of X5K664 may comprise at least onetransgene but could contain at least 1, 2, 3, 4, 5, 6, 7, 8, 9, 10and/or no more than 15, 14, 13, 12, 11, 10, 9, 8, 7, 6, 5, 4, 3, or 2.Over the last fifteen to twenty years several methods for producingtransgenic plants have been developed, and the present invention alsorelates to transformed versions of the claimed hybrid maize X5K664 aswell as combinations thereof.

Numerous methods for plant transformation have been developed, includingbiological and physical plant transformation protocols. See, forexample, Miki et al., “Procedures for Introducing Foreign DNA intoPlants” in Methods in Plant Molecular Biology and Biotechnology, Glick,B. R. and Thompson, J. E. Eds. (CRC Press, Inc., Boca Raton, 1993) pages67-88 and Armstrong, “The First Decade of Maize Transformation: A Reviewand Future Perspective” (Maydica 44:101-109, 1999). In addition,expression vectors and in vitro culture methods for plant cell or tissuetransformation and regeneration of plants are available. See, forexample, Gruber et al., “Vectors for Plant Transformation” in Methods inPlant Molecular Biology and Biotechnology, Glick, B. R. and Thompson, J.E. Eds. (CRC Press, Inc., Boca Raton, 1993) pages 89-119.

The most prevalent types of plant transformation involve theconstruction of an expression vector. Such a vector comprises a DNAsequence that contains a gene under the control of or operatively linkedto a regulatory element, for example a promoter. The vector may containone or more genes and one or more regulatory elements.

A genetic trait which has been engineered into the genome of aparticular maize plant using transformation techniques, could be movedinto the genome of another variety using traditional breeding techniquesthat are well known in the plant breeding arts. These varieties can thenbe crossed to generate a hybrid maize plant such as hybrid maize plantX5K664 which comprises a transgene. For example, a backcrossing approachis commonly used to move a transgene from a transformed maize plant toan elite inbred variety, and the resulting progeny would then comprisethe transgene(s). Also, if an inbred variety was used for thetransformation then the transgenic plants could be crossed to adifferent inbred in order to produce a transgenic hybrid maize plant.

Various genetic elements can be introduced into the plant genome usingtransformation. These elements include, but are not limited to genes;coding sequences; inducible, constitutive, and tissue specificpromoters; enhancing sequences; and signal and targeting sequences. Forexample, see the traits, genes and transformation methods listed in U.S.Pat. Nos. 6,118,055 and 6,284,953, which are herein incorporated byreference. In addition, transformability of a variety can be increasedby introgressing the trait of high transformability from another varietyknown to have high transformability, such as Hi-II. See U.S. PatentApplication Publication No. 2004/0016030.

With transgenic plants according to the present invention, a foreignprotein can be produced in commercial quantities. Thus, techniques forthe selection and propagation of transformed plants, which are wellunderstood in the art, yield a plurality of transgenic plants that areharvested in a conventional manner, and a foreign protein then can beextracted from a tissue of interest or from total biomass. Proteinextraction from plant biomass can be accomplished by known methods whichare discussed, for example, by Heney and Orr, Anal. Biochem. 114: 92-6(1981).

Transgenes can be mapped by one of ordinary skill in the art and suchtechniques are well known to those of ordinary skill in the art. Forexemplary methodologies in this regard, see for example, Glick andThompson, Methods In Plant Molecular Biology And Biotechnology, 269-284(CRC Press, Boca Raton, 1993).

Likewise, by means of the present invention, plants can be geneticallyengineered to express various phenotypes of agronomic interest. Throughthe transformation of maize the expression of genes can be altered toenhance disease resistance, insect resistance, herbicide resistance,agronomic traits, grain quality and other traits. Transformation canalso be used to insert DNA sequences which control or help controlmale-sterility. DNA sequences native to maize as well as non-native DNAsequences can be transformed into maize and used to alter levels ofnative or non-native proteins. Various promoters, targeting sequences,enhancing sequences, and other DNA sequences can be inserted into themaize genome for the purpose of altering the expression of proteins.Reduction of the activity of specific genes (also known as genesilencing, or gene suppression) is desirable for several aspects ofgenetic engineering in plants.

Many techniques for gene silencing are well known to one of skill in theart, including but not limited to knock-outs (such as by insertion of atransposable element such as mu (Vicki Chandler, The Maize Handbook ch.118 (Springer-Verlag 1994) or other genetic elements such as a FRT, Loxor other site specific integration site, antisense technology (see,e.g., Sheehy et al. (1988) PNAS USA 85:8805-8809; and U.S. Pat. Nos.5,107,065; 5,453, 566; and 5,759,829); co-suppression (e.g., Taylor(1997) Plant Cell 9:1245; Jorgensen (1990) Trends Biotech.8(12):340-344; Flavell (1994) PNAS USA 91:3490-3496; Finnegan et al.(1994) Bio/Technology 12: 883-888; and Neuhuber et al. (1994) Mol. Gen.Genet. 244:230-241); RNA interference (Napoli et al. (1990) Plant Cell2:279-289; U.S. Pat. No. 5,034,323; Sharp (1999) Genes Dev. 13:139-141;Zamore et al. (2000) Cell 101:25-33; and Montgomery et al. (1998) PNASUSA 95:15502-15507), virus-induced gene silencing (Burton, et al. (2000)Plant Cell 12:691-705; and Baulcombe (1999) Curr. Op. Plant Bio.2:109-113); target-RNA-specific ribozymes (Haseloff et al. (1988) Nature334: 585-591); hairpin structures (Smith et al. (2000) Nature407:319-320; WO 99/53050; and WO 98/53083); MicroRNA (Aukerman & Sakai(2003) Plant Cell 15:2730-2741); ribozymes (Steinecke et al. (1992) EMBOJ. 11:1525; and Perriman et al. (1993) Antisense Res. Dev. 3:253);oligonucleotide mediated targeted modification (e.g., WO 03/076574 andWO 99/25853); Zn-finger targeted molecules (e.g., WO 01/52620; WO03/048345; and WO 00/42219); and other methods or combinations of theabove methods known to those of skill in the art.

Exemplary nucleotide sequences that may be altered by geneticengineering include, but are not limited to, those categorized below.

1. Transgenes That Confer Resistance To Insects or Disease And ThatEncode:

(A) Plant disease resistance genes. Plant defenses are often activatedby specific interaction between the product of a disease resistance gene(R) in the plant and the product of a corresponding avirulence (Avr)gene in the pathogen. A plant variety can be transformed with clonedresistance gene to engineer plants that are resistant to specificpathogen strains. See, for example Jones et al., Science 266: 789 (1994)(cloning of the tomato Cf-9 gene for resistance to Cladosporium fulvum);Martin et al., Science 262: 1432 (1993) (tomato Pto gene for resistanceto Pseudomonas syringae pv. tomato encodes a protein kinase); Mindrinoset al., Cell 78: 1089 (1994) (Arabidopsis RSP2 gene for resistance toPseudomonas syringae); McDowell & Woffenden, (2003) Trends Biotechnol.21(4): 178-83 and Toyoda et al., (2002) Transgenic Res. 11 (6):567-82. Aplant resistant to a disease is one that is more resistant to a pathogenas compared to the wild type plant.

(B) A Bacillus thuringiensis protein, a derivative thereof or asynthetic polypeptide modeled thereon. See, for example, Geiser et al.,Gene 48: 109 (1986), who disclose the cloning and nucleotide sequence ofa Bt delta-endotoxin gene. Moreover, DNA molecules encodingdelta-endotoxin genes can be purchased from American Type CultureCollection (Rockville, Md.), for example, under ATCC Accession Nos.40098, 67136, 31995 and 31998. Other examples of Bacillus thuringiensistransgenes being genetically engineered are given in the followingpatents and patent applications and hereby are incorporated by referencefor this purpose: U.S. Pat. Nos. 5,188,960; 5,689,052; 5,880,275; WO91/14778; WO 99/31248; WO 01/12731; WO 99/24581; WO 97/40162 and U.S.application Ser. Nos. 10/032,717; 10/414,637; and 10/606,320.

(C) An insect-specific hormone or pheromone such as an ecdysteroid andjuvenile hormone, a variant thereof, a mimetic based thereon, or anantagonist or agonist thereof. See, for example, the disclosure byHammock et al., Nature 344: 458 (1990), of baculovirus expression ofcloned juvenile hormone esterase, an inactivator of juvenile hormone.

(D) An insect-specific peptide which, upon expression, disrupts thephysiology of the affected pest. For example, see the disclosures ofRegan, J. Biol. Chem. 269: 9 (1994) (expression cloning yields DNAcoding for insect diuretic hormone receptor); Pratt et al., Biochem.Biophys. Res. Comm. 163: 1243 (1989) (an allostatin is identified inDiploptera puntata); Chattopadhyay et al. (2004) Critical Reviews inMicrobiology 30 (1): 33-54 2004; Zjawiony (2004) J Nat Prod 67 (2):300-310; Carlini & Grossi-de-Sa (2002) Toxicon, 40 (11): 1515-1539;Ussuf et al. (2001) Curr Sci. 80 (7): 847-853; and Vasconcelos &Oliveira (2004) Toxicon 44 (4): 385-403. See also U.S. Pat. No.5,266,317 to Tomalski et al., who disclose genes encodinginsect-specific toxins.

(E) An enzyme responsible for a hyperaccumulation of a monterpene, asesquiterpene, a steroid, hydroxamic acid, a phenylpropanoid derivativeor another non-protein molecule with insecticidal activity.

(F) An enzyme involved in the modification, including thepost-translational modification, of a biologically active molecule; forexample, a glycolytic enzyme, a proteolytic enzyme, a lipolytic enzyme,a nuclease, a cyclase, a transaminase, an esterase, a hydrolase, aphosphatase, a kinase, a phosphorylase, a polymerase, an elastase, achitinase and a glucanase, whether natural or synthetic. See PCTApplication WO 93/02197 in the name of Scott et al., which discloses thenucleotide sequence of a callase gene. DNA molecules which containchitinase-encoding sequences can be obtained, for example, from the ATCCunder Accession Nos. 39637 and 67152. See also Kramer et al., InsectBiochem. Molec. Biol. 23: 691 (1993), who teach the nucleotide sequenceof a cDNA encoding tobacco hookworm chitinase, and Kawalleck et al.,Plant Molec. Biol. 21: 673 (1993), who provide the nucleotide sequenceof the parsley ubi4-2 polyubiquitin gene, U.S. application Ser. Nos.10/389,432, 10/692,367, and U.S. Pat. No. 6,563,020.

(G) A molecule that stimulates signal transduction. For example, see thedisclosure by Botella et al., Plant Molec. Biol. 24: 757 (1994), ofnucleotide sequences for mung bean calmodulin cDNA clones, and Griess etal., Plant Physiol. 104: 1467 (1994), who provide the nucleotidesequence of a maize calmodulin cDNA clone.

(H) A hydrophobic moment peptide. See PCT Application WO 95/16776 andU.S. Pat. No. 5,580,852 (disclosure of peptide derivatives ofTachyplesin which inhibit fungal plant pathogens) and PCT Application WO95/18855 and U.S. Pat. No. 5,607,914 (teaches synthetic antimicrobialpeptides that confer disease resistance).

(I) A membrane permease, a channel former or a channel blocker. Forexample, see the disclosure by Jaynes et al., Plant Sci. 89: 43 (1993),of heterologous expression of a cecropin-beta lytic peptide analog torender transgenic tobacco plants resistant to Pseudomonas solanacearum.

(J) A viral-invasive protein or a complex toxin derived therefrom. Forexample, the accumulation of viral coat proteins in transformed plantcells imparts resistance to viral infection and/or disease developmenteffected by the virus from which the coat protein gene is derived, aswell as by related viruses. See Beachy et al., Ann. Rev. Phytopathol.28: 451 (1990). Coat protein-mediated resistance has been conferred upontransformed plants against alfalfa mosaic virus, cucumber mosaic virus,tobacco streak virus, potato virus X, potato virus Y, tobacco etchvirus, tobacco rattle virus and tobacco mosaic virus. Id.

(K) An insect-specific antibody or an immunotoxin derived therefrom.Thus, an antibody targeted to a critical metabolic function in theinsect gut would inactivate an affected enzyme, killing the insect. CfTaylor et al., Abstract #497, Seventh Int'l Symposium On MolecularPlant-Microbe Interactions (Edinburgh, Scotland, 1994) (enzymaticinactivation in transgenic tobacco via production of single-chainantibody fragments).

(L) A virus-specific antibody. See, for example, Tavladoraki et al.,Nature 366: 469 (1993), who show that transgenic plants expressingrecombinant antibody genes are protected from virus attack.

(M) A developmental-arrestive protein produced in nature by a pathogenor a parasite. Thus, fungal endo alpha-1,4-D-polygalacturonasesfacilitate fungal colonization and plant nutrient release bysolubilizing plant cell wall homo-alpha-1,4-D-galacturonase. See Lamb etal., Bio/Technology 10: 1436 (1992). The cloning and characterization ofa gene which encodes a bean endopolygalacturonase-inhibiting protein isdescribed by Toubart et al., Plant J. 2: 367 (1992).

(N) A developmental-arrestive protein produced in nature by a plant. Forexample, Logemann et al., Bio/Technology 10: 305 (1992), have shown thattransgenic plants expressing the barley ribosome-inactivating gene havean increased resistance to fungal disease.

(O) Genes involved in the Systemic Acquired Resistance (SAR) Responseand/or the pathogenesis related genes. Briggs, S., Current Biology,5(2):128-131 (1995), Pieterse & Van Loon (2004) Curr. Opin. Plant Bio.7(4):456-64 and Somssich (2003) Cell 113(7):815-6.

(P) Antifungal genes (Cornelissen and Melchers, P I. Physiol.101:709-712, (1993) and Parijs et al., Planta 183:258-264, (1991) andBushnell et al., Can. J. of Plant Path. 20(2):137-149 (1998). Also seeU.S. Pat. No. 6,875,907.

(Q) Detoxification genes, such as for fumonisin, beauvericin,moniliformin and zearalenone and their structurally related derivatives.For example, see U.S. Pat. No. 5,792,931.

(R) Cystatin and cysteine proteinase inhibitors. See U.S. applicationSer. No. 10/947,979.

(S) Defensin genes. See WO 03/000863 and U.S. application Ser. No.10/178,213.

(T) Genes conferring resistance to nematodes. See WO 03/033651 and Urwinet al., Planta 204:472-479 (1998), Williamson (1999) Curr Opin PlantBio. 2(4):327-31.

(U) Genes such as rcg1 conferring resistance to Anthracnose stalk rot,which is caused by the fungus Colletotrichum graminiola. See M. Jung etal., Generation-means analysis and quantitative trait locus mapping ofAnthracnose Stalk Rot genes in Maize, Theor. Appl. Genet. (1994)89:413-418 which is incorporated by reference for this purpose, as wellas U.S. Patent Application 60/675,664, which is also incorporated byreference for this purpose.

2. Transgenes That Confer Resistance To A Herbicide, For Example:

(A) A herbicide that inhibits the growing point or meristem, such as animidazolinone or a sulfonylurea. Exemplary genes in this category codefor mutant ALS and AHAS enzyme as described, for example, by Lee et al.,EMBO J. 7: 1241 (1988), and Miki et al., Theor. Appl. Genet. 80: 449(1990), respectively. See also, U.S. Pat. Nos. 5,605,011; 5,013,659;5,141,870; 5,767,361; 5,731,180; 5,304,732; 4,761,373; 5,331,107;5,928,937; and 5,378,824; and international publication WO 96/33270,which are incorporated herein by reference for this purpose.

(B) Glyphosate (resistance imparted by mutant5-enolpyruvl-3-phosphikimate synthase (EPSP), and aroA genes,respectively) and other phosphono compounds such as glufosinate(phosphinothricin acetyl transferase (PAT) and Streptomyceshygroscopicus phosphinothricin acetyl transferase (bar) genes), andpyridinoxy or phenoxy proprionic acids and cycloshexones (ACCaseinhibitor-encoding genes). See, for example, U.S. Pat. No. 4,940,835 toShah et al., which discloses the nucleotide sequence of a form of EPSPSwhich can confer glyphosate resistance. U.S. Pat. No. 5,627,061 to Barryet al. also describes genes encoding EPSPS enzymes. See also U.S. Pat.Nos. 6,566,587; 6,338,961; 6,248,876 B1; 6,040,497; 5,804,425;5,633,435; 5,145,783; 4,971,908; 5,312,910; 5,188,642; 4,940,835;5,866,775; 6,225,114 B1; 6,130,366; 5,310,667; 4,535,060; 4,769,061;5,633,448; 5,510,471; Re. 36,449; RE 37,287 E; and 5,491,288; andinternational publications EP1173580; WO 01/66704; EP1173581 and EP1173582, which are incorporated herein by reference for this purpose.Glyphosate resistance is also imparted to plants that express a genethat encodes a glyphosate oxido-reductase enzyme as described more fullyin U.S. Pat. Nos. 5,776,760 and 5,463,175, which are incorporated hereinby reference for this purpose. In addition glyphosate resistance can beimparted to plants by the over expression of genes encoding glyphosateN-acetyltransferase. See, for example, U.S. application Ser. Nos.10/427,692, 11/405,845, 11/433,132, 11/433,880, 11/504,877, 11/505,102and PCT US01/46227. A DNA molecule encoding a mutant aroA gene can beobtained under ATCC Accession No. 39256, and the nucleotide sequence ofthe mutant gene is disclosed in U.S. Pat. No. 4,769,061 to Comai.European Patent Application No. 0 333 033 to Kumada et al. and U.S. Pat.No. 4,975,374 to Goodman et al. disclose nucleotide sequences ofglutamine synthetase genes which confer resistance to herbicides such asL-phosphinothricin. The nucleotide sequence of aphosphinothricin-acetyl-transferase gene is provided in European PatentNo. 0 242 246 and 0 242 236 to Leemans et al. De Greef et al.,Bio/Technology 7: 61 (1989), describe the production of transgenicplants that express chimeric bargenes coding for phosphinothricin acetyltransferase activity. See also, U.S. Pat. Nos. 5,969,213; 5,489,520;5,550,318; 5,874,265; 5,919,675; 5,561,236; 5,648,477; 5,646,024;6,177,616 B1; and 5,879,903, which are incorporated herein by referencefor this purpose. Exemplary genes conferring resistance to phenoxyproprionic acids and cycloshexones, such as sethoxydim and haloxyfop,are the Acc1-S1, Acc1-S2 and Acc1-S3 genes described by Marshall et al.,Theor. Appl. Genet. 83: 435 (1992).

(C) A herbicide that inhibits photosynthesis, such as a triazine (psbAand gs+ genes) and a benzonitrile (nitrilase gene). Przibilla et al.,Plant Cell 3: 169 (1991), describe the transformation of Chlamydomonaswith plasmids encoding mutant psbA genes. Nucleotide sequences fornitrilase genes are disclosed in U.S. Pat. No. 4,810,648 to Stalker, andDNA molecules containing these genes are available under ATCC AccessionNos. 53435, 67441 and 67442. Cloning and expression of DNA coding for aglutathione S-transferase is described by Hayes et al., Biochem. J.285:173 (1992).

(D) Acetohydroxy acid synthase, which has been found to make plants thatexpress this enzyme resistant to multiple types of herbicides, has beenintroduced into a variety of plants (see, e.g., Hattori et al. (1995)Mol Gen Genet 246:419). Other genes that confer resistance to herbicidesinclude: a gene encoding a chimeric protein of rat cytochrome P4507A1and yeast NADPH-cytochrome P450 oxidoreductase (Shiota et al. (1994)Plant Physiol. 106(1):17-23), genes for glutathione reductase andsuperoxide dismutase (Aono et al. (1995) Plant Cell Physiol. 36:1687,and genes for various phosphotransferases (Datta et al. (1992) PlantMol. Biol. 20:619).

(E) Protoporphyrinogen oxidase (protox) is necessary for the productionof chlorophyll, which is necessary for all plant survival. The protoxenzyme serves as the target for a variety of herbicidal compounds. Theseherbicides also inhibit growth of all the different species of plantspresent, causing their total destruction. The development of plantscontaining altered protox activity which are resistant to theseherbicides are described in U.S. Pat. Nos. 6,288,306 B1; 6,282,837 B1;and 5,767,373; and international publication WO 01/12825.

3. Transgenes That Confer Or Contribute To An Altered GrainCharacteristic, Such As:

(A) Altered fatty acids, for example, by

-   -   (1) Down-regulation of stearoyl-ACP desaturase to increase        stearic acid content of the plant. See Knultzon et al., Proc.        Natl. Acad. Sci. USA 89: 2624 (1992) and WO99/64579 (Genes for        Desaturases to Alter Lipid Profiles in Corn),    -   (2) Elevating oleic acid via FAD-2 gene modification and/or        decreasing linolenic acid via FAD-3 gene modification (see U.S.        Pat. Nos. 6,063,947; 6,323,392; 6,372,965 and WO 93/11245),    -   (3) Altering conjugated linolenic or linoleic acid content, such        as in WO 01/12800,    -   (4) Altering LEC1, AGP, Dek1, Superal1, mi1ps, various Ipa genes        such as Ipa1, Ipa3, hpt or hggt. For example, see WO 02/42424,        WO 98/22604, WO 03/011015, WO02/057439, WO03/011015, U.S. Pat.        Nos. 6,423,886, 6,197,561, 6,825,397, and U.S. Application        Serial Nos. US2003/0079247, US2003/0204870, and        Rivera-Madrid, R. et al. Proc. Natl. Acad. Sci. 92:5620-5624        (1995).

(B) Altered phosphorus content, for example, by the

-   -   (1) Introduction of a phytase-encoding gene would enhance        breakdown of phytate, adding more free phosphate to the        transformed plant. For example, see Van Hartingsveldt et al.,        Gene 127: 87 (1993), for a disclosure of the nucleotide sequence        of an Aspergillus niger phytase gene.    -   (2) Up-regulation of a gene that reduces phytate content. In        maize, this, for example, could be accomplished, by cloning and        then re-introducing DNA associated with one or more of the        alleles, such as the LPA alleles, identified in maize mutants        characterized by low levels of phytic acid, such as in Raboy et        al., Maydica 35: 383 (1990) and/or by altering inositol kinase        activity as in WO 02/059324, US2003/0009011, WO 03/027243,        US2003/0079247, WO 99/05298, U.S. Pat. No. 6,197,561, U.S. Pat.        No. 6,291,224, U.S. Pat. No. 6,391,348, WO2002/059324,        US2003/0079247, WO98/45448, WO99/55882, WO01/04147.

(C) Altered carbohydrates effected, for example, by altering a gene foran enzyme that affects the branching pattern of starch, a gene alteringthioredoxin such as NTR and/or TRX (see U.S. Pat. No. 6,531,648, whichis incorporated by reference for this purpose) and/or a gamma zein knockout or mutant such as cs27 or TUSC27 or en27 (See U.S. Pat. No.6,858,778 and US2005/0160488, US2005/0204418, which are incorporated byreference for this purpose). See Shiroza et al., J. Bacteriol. 170: 810(1988) (nucleotide sequence of Streptococcus mutans fructosyltransferasegene), Steinmetz et al., Mol. Gen. Genet. 200: 220 (1985) (nucleotidesequence of Bacillus subtilis levansucrase gene), Pen et al.,Bio/Technology 10: 292 (1992) (production of transgenic plants thatexpress Bacillus licheniformis alpha-amylase), Elliot et al., PlantMolec. Biol. 21: 515 (1993) (nucleotide sequences of tomato invertasegenes), Søgaard et al., J. Biol. Chem. 268: 22480 (1993) (site-directedmutagenesis of barley alpha-amylase gene), and Fisher et al., PlantPhysiol. 102: 1045 (1993) (maize endosperm starch branching enzyme II),WO 99/10498 (improved digestibility and/or starch extraction throughmodification of UDP-D-xylose 4-epimerase, Fragile 1 and 2, Ref1, HCHL,C4H), U.S. Pat. No. 6,232,529 (method of producing high oil seed bymodification of starch levels (AGP)). The fatty acid modification genesmentioned above may also be used to affect starch content and/orcomposition through the interrelationship of the starch and oilpathways.

(D) Altered antioxidant content or composition, such as alteration oftocopherol or tocotrienols. For example, see U.S. Pat. No. 6,787,683,US2004/0034886 and WO 00/68393 involving the manipulation of antioxidantlevels through alteration of a phytl prenyl transferase (ppt), WO03/082899 through alteration of a homogentisate geranyl geranyltransferase (hggt).

(E) Altered essential seed amino acids. For example, see U.S. Pat. No.6,127,600 (method of increasing accumulation of essential amino acids inseeds), U.S. Pat. No. 6,080,913 (binary methods of increasingaccumulation of essential amino acids in seeds), U.S. Pat. No. 5,990,389(high lysine), WO99/40209 (alteration of amino acid compositions inseeds), WO99/29882 (methods for altering amino acid content ofproteins), U.S. Pat. No. 5,850,016 (alteration of amino acidcompositions in seeds), WO98/20133 (proteins with enhanced levels ofessential amino acids), U.S. Pat. No. 5,885,802 (high methionine), U.S.Pat. No. 5,885,801 (high threonine), U.S. Pat. No. 6,664,445 (plantamino acid biosynthetic enzymes), U.S. Pat. No. 6,459,019 (increasedlysine and threonine), U.S. Pat. No. 6,441,274 (plant tryptophansynthase beta subunit), U.S. Pat. No. 6,346,403 (methionine metabolicenzymes), U.S. Pat. No. 5,939,599 (high sulfur), U.S. Pat. No. 5,912,414(increased methionine), WO98/56935 (plant amino acid biosyntheticenzymes), WO98/45458 (engineered seed protein having higher percentageof essential amino acids), WO98/42831 (increased lysine), U.S. Pat. No.5,633,436 (increasing sulfur amino acid content), U.S. Pat. No.5,559,223 (synthetic storage proteins with defined structure containingprogrammable levels of essential amino acids for improvement of thenutritional value of plants), WO96/01905 (increased threonine),WO95/15392 (increased lysine), US2003/0163838, US2003/0150014,US2004/0068767, U.S. Pat. No. 6,803,498, WO01/79516, and WO00/09706 (CesA: cellulose synthase), U.S. Pat. No. 6,194,638 (hemicellulose), U.S.Pat. No. 6,399,859 and US2004/0025203 (UDPGdH), U.S. Pat. No. 6,194,638(RGP).

4. Genes that Control Male-sterility:

There are several methods of conferring genetic male sterilityavailable, such as multiple mutant genes at separate locations withinthe genome that confer male sterility, as disclosed in U.S. Pat. Nos.4,654,465 and 4,727,219 to Brar et al. and chromosomal translocations asdescribed by Patterson in U.S. Pat. Nos. 3,861,709 and 3,710,511. Inaddition to these methods, Albertsen et al., U.S. Pat. No. 5,432,068,describe a system of nuclear male sterility which includes: identifyinga gene which is critical to male fertility; silencing this native genewhich is critical to male fertility; removing the native promoter fromthe essential male fertility gene and replacing it with an induciblepromoter; inserting this genetically engineered gene back into theplant; and thus creating a plant that is male sterile because theinducible promoter is not “on” resulting in the male fertility gene notbeing transcribed. Fertility is restored by inducing, or turning “on”,the promoter, which in turn allows the gene that confers male fertilityto be transcribed.

(A) Introduction of a deacetylase gene under the control of atapetum-specific promoter and with the application of the chemicalN-Ac-PPT (WO 01/29237).

(B) Introduction of various stamen-specific promoters (WO 92/13956, WO92/13957).

(C) Introduction of the barnase and the barstar gene (Paul et al. PlantMol. Biol. 19:611-622, 1992).

For additional examples of nuclear male and female sterility systems andgenes, see also, U.S. Pat. Nos. 5,859,341; 6,297,426; 5,478,369;5,824,524; 5,850,014; and 6,265,640; all of which are herebyincorporated by reference.

5. Genes that create a site for site specific DNA integration. Thisincludes the introduction of FRT sites that may be used in the FLP/FRTsystem and/or Lox sites that may be used in the Cre/Loxp system. Forexample, see Lyznik, et al., Site-Specific Recombination for GeneticEngineering in Plants, Plant Cell Rep (2003) 21:925-932 and WO 99/25821which are hereby incorporated by reference. Other systems that may beused include the Gin recombinase of phage Mu (Maeser et al., 1991; VickiChandler, The Maize Handbook ch. 118 (Springer-Verlag 1994), the Pinrecombinase of E. coli (Enomoto et al., 1983), and the R/RS system ofthe pSR1 plasmid (Araki et al., 1992).6. Genes that affect abiotic stress resistance (including but notlimited to flowering, ear and seed development, enhancement of nitrogenutilization efficiency, altered nitrogen responsiveness, droughtresistance or tolerance, cold resistance or tolerance, and saltresistance or tolerance) and increased yield under stress. For example,see: WO 00/73475 where water use efficiency is altered throughalteration of malate; U.S. Pat. Nos. 5,892,009, 5,965,705, 5,929,305,5,891,859, 6,417,428, 6,664,446, 6,706,866, 6,717,034, 6,801,104,WO2000060089, WO2001026459, WO2001035725, WO2001034726, WO2001035727,WO2001036444, WO2001036597, WO2001036598, WO2002015675, WO2002017430,WO2002077185, WO2002079403, WO2003013227, WO2003013228, WO2003014327,WO2004031349, WO2004076638, WO9809521, and WO9938977 describing genes,including CBF genes and transcription factors effective in mitigatingthe negative effects of freezing, high salinity, and drought on plants,as well as conferring other positive effects on plant phenotype;US2004/0148654 and WO01/36596 where abscisic acid is altered in plantsresulting in improved plant phenotype such as increased yield and/orincreased tolerance to abiotic stress; WO2000/006341, WO04/090143, U.S.application Ser. Nos. 10/817,483 and 09/545,334 where cytokininexpression is modified resulting in plants with increased stresstolerance, such as drought tolerance, and/or increased yield. Also seeWO0202776, WO2003052063, JP2002281975, U.S. Pat. No. 6,084,153,WO0164898, U.S. Pat. No. 6,177,275, and U.S. Pat. No. 6,107,547(enhancement of nitrogen utilization and altered nitrogenresponsiveness). For ethylene alteration, see US20040128719,US20030166197 and WO200032761. For plant transcription factors ortranscriptional regulators of abiotic stress, see e.g. US20040098764 orUS20040078852.

Other genes and transcription factors that affect plant growth andagronomic traits such as yield, flowering, plant growth and/or plantstructure, can be introduced or introgressed into plants, see e.g.WO97/49811 (LHY), WO98/56918 (ESD4), WO97/10339 and U.S. Pat. No.6,573,430 (TFL), U.S. Pat. No. 6,713,663 (FT), WO96/14414 (CON),WO96/38560, WO01/21822 (VRN1), WO00/44918 (VRN2), WO99/49064 (GI),WO00/46358 (FRI), WO97/29123, U.S. Pat. No. 6,794,560, U.S. Pat. No.6,307,126 (GAI), WO99/09174 (D8 and Rht), and WO2004076638 andWO2004031349 (transcription factors).

Using X5K664 to Develop Another Maize Plant

The development of maize hybrids in a maize plant breeding programrequires, in general, the development of homozygous inbred lines, thecrossing of these lines, and the evaluation of the crosses. Maize plantbreeding programs combine the genetic backgrounds from two or moreinbred varieties or various other germplasm sources into breedingpopulations from which new inbred varieties are developed by selfing andselection of desired phenotypes. Hybrids also can be used as a source ofplant breeding material or as source populations from which to developor derive new maize varieties. Plant breeding techniques known in theart and used in a maize plant breeding program include, but are notlimited to, recurrent selection, mass selection, bulk selection,backcrossing, making double haploids, pedigree breeding, openpollination breeding, restriction fragment length polymorphism enhancedselection, genetic marker enhanced selection, and transformation. Oftencombinations of these techniques are used. The inbred varieties derivedfrom hybrids can be developed using plant breeding techniques asdescribed above. New inbreds are crossed with other inbred varieties andthe hybrids from these crosses are evaluated to determine which of thosehave commercial potential. The oldest and most traditional method ofanalysis is the observation of phenotypic traits but genotypic analysismay also be used. Descriptions of breeding methods can also be found inone of several reference books (e.g., Allard, Principles of PlantBreeding, 1960; Simmonds, Principles of Crop Improvement, 1979; Fehr,“Breeding Methods for Cultivar Development”, Production and Uses, 2^(nd)ed., Wilcox editor, 1987).

Recurrent Selection and Mass Selection

Recurrent selection is a method used in a plant breeding program toimprove a population of plants. X5K664 is suitable for use in arecurrent selection program. The method entails individual plants crosspollinating with each other to form progeny. The progeny are grown andthe superior progeny selected by any number of selection methods, whichinclude individual plant, half-sib progeny, full-sib progeny, selfedprogeny and topcrossing. The selected progeny are cross pollinated witheach other to form progeny for another population. This population isplanted and again superior plants are selected to cross pollinate witheach other. Recurrent selection is a cyclical process and therefore canbe repeated as many times as desired. The objective of recurrentselection is to improve the traits of a population. The improvedpopulation can then be used as a source of breeding material to obtaininbred varieties to be used in hybrids or used as parents for asynthetic cultivar. A synthetic cultivar is the resultant progeny formedby the intercrossing of several selected inbreds.

X5K664 is suitable for use in mass selection. Mass selection is a usefultechnique when used in conjunction with molecular marker enhancedselection. In mass selection seeds from individuals are selected basedon phenotype and/or genotype. These selected seeds are then bulked andused to grow the next generation. Bulk selection requires growing apopulation of plants in a bulk plot, allowing the plants toself-pollinate, harvesting the seed in bulk and then using a sample ofthe seed harvested in bulk to plant the next generation. Instead of selfpollination, directed pollination could be used as part of the breedingprogram.

Mutation Breeding

Mutation breeding is one of many methods that could be used to introducenew traits into X5K664 by mutating one or more of the parental maizeinbred varieties of X5K664. X5K664 is suitable for use in a mutationbreeding program. Mutations that occur spontaneously or are artificiallyinduced can be useful sources of variability for a plant breeder. Thegoal of artificial mutagenesis is to increase the rate of mutation for adesired characteristic. Mutation rates can be increased by manydifferent means including temperature, long-term seed storage, tissueculture conditions, radiation; such as X-rays, Gamma rays (e.g. cobalt60 or cesium 137), neutrons, (product of nuclear fission by uranium 235in an atomic reactor), Beta radiation (emitted from radioisotopes suchas phosphorus 32 or carbon 14), or ultraviolet radiation (preferablyfrom 2500 to 2900 nm), or chemical mutagens (such as base analogues(5-bromo-uracil), related compounds (8-ethoxy caffeine), antibiotics(streptonigrin), alkylating agents (sulfur mustards, nitrogen mustards,epoxides, ethylenamines, sulfates, sulfonates, sulfones, lactones),azide, hydroxylamine, nitrous acid, or acridines. Once a desired traitis observed through mutagenesis the trait may then be incorporated intoexisting germplasm by traditional breeding techniques, such asbackcrossing. Details of mutation breeding can be found in “Principlesof Cultivar Development” Fehr, 1993 Macmillan Publishing Company, thedisclosure of which is incorporated herein by reference. In addition,mutations created in other varieties may be used to produce a backcrossconversion of X5K664 that comprises such mutation.

Breeding with Molecular Markers

Molecular markers, which includes markers identified through the use oftechniques such as Isozyme Electrophoresis, Restriction Fragment LengthPolymorphisms (RFLPs), Randomly Amplified Polymorphic DNAs (RAPDs),Arbitrarily Primed Polymerase Chain Reaction (AP-PCR), DNA AmplificationFingerprinting (DAF), Sequence Characterized Amplified Regions (SCARs),Amplified Fragment Length Polymorphisms (AFLPs), Single NucleotidePolymorphisms (SNPs) and Simple Sequence Repeats (SSRs) may be used onX5K664.

Isozyme Electrophoresis and RFLPs as discussed in Lee, M., “Inbred Linesof Maize and Their Molecular Markers,” The Maize Handbook,(Springer-Verlag, New York, Inc. 1994, at 423-432) incorporated hereinby reference, have been widely used to determine genetic composition.Isozyme Electrophoresis has a relatively low number of available markersand a low number of allelic variants. RFLPs allow more discriminationbecause they have a higher degree of allelic variation in maize and alarger number of markers can be found. Both of these methods have beeneclipsed by SSRs as discussed in Smith et al., “An evaluation of theutility of SSR loci as molecular markers in maize (Zea mays L.):comparisons with data from RFLPs and pedigree”, Theoretical and AppliedGenetics (1997) vol. 95 at 163-173 and by Pejic et al., “Comparativeanalysis of genetic similarity among maize inbreds detected by RFLPs,RAPDs, SSRs, and AFLPs,” Theoretical and Applied Genetics (1998) at1248-1255 incorporated herein by reference. SSR technology is moreefficient and practical to use than RFLPs; more marker loci can beroutinely used and more alleles per marker locus can be found using SSRsin comparison to RFLPs. Single Nucleotide Polymorphisms may also be usedto identify the unique genetic composition of the invention and progenyvarieties retaining that unique genetic composition. Various molecularmarker techniques may be used in combination to enhance overallresolution.

Maize DNA molecular marker linkage maps have been rapidly constructedand widely implemented in genetic studies. One such study is describedin Boppenmaier, et al., “Comparisons among strains of inbreds forRFLPs”, Maize Genetics Cooperative Newsletter, 65:1991, pg. 90, isincorporated herein by reference.

A genetic marker profile of a hybrid should be the sum of its inbredparents, e.g., if one inbred parent is homozygous for allele x at aparticular locus, and the other inbred parent is homozygous for allele yat that locus, the F1 hybrid will be x.y (heterozygous) at that locus.The profile can therefore be used to identify the inbred parents ofhybrid X5K664. The determination of the male set of alleles and thefemale set of alleles may be made by profiling the hybrid and thepericarp of the hybrid seed, which is composed of maternal parent cells.The paternal parent profile is obtained by subtracting the pericarpprofile from the hybrid profile.

Molecular markers can also be used to reduce the number of crosses backto the recurrent parent needed in a backcrossing program. Withbackcrossing, the expected contribution of a parental maize inbredvariety of maize hybrid variety X5K664 after 2, 3, 4 and 5 doses (or 1,2, 3 and 4 backcrosses) would be 75%, 87.5%, 93.75% and 96.875%respectively. Actual genetic contribution may be much higher than thegenetic contribution expected by pedigree, especially if molecularmarkers are used in selection. The use of molecular markers in theselection process is often called genetic marker enhanced selection.

Production of Double Haploids

The production of double haploids can also be used for the developmentof inbreds. Double haploids are produced by the doubling of a set ofchromosomes (1N) from a heterozygous plant to produce a completelyhomozygous individual. For example, a further embodiment of thisinvention is the method of obtaining a substantially homozygous X5K664progeny plant by obtaining a seed from the cross of X5K664 and anothermaize plant and applying double haploid methods to the F1 seed or F1plant or to any successive filial generation. Such methods substantiallydecrease the number of generations required to produce an inbred withsimilar genetics or characteristics to X5K664. For example, see Wan etal., “Efficient Production of Doubled Haploid Plants Through ColchicineTreatment of Anther-Derived Maize Callus”, Theoretical and AppliedGenetics, 77:889-892, 1989 and U.S. Patent Application 2003/0005479.This can be advantageous because the process omits the generations ofselfing needed to obtain a homozygous plant from a heterozygous source.

Haploid induction systems have been developed for various plants toproduce haploid tissues, plants and seeds. The haploid induction systemcan produce haploid plants from any genotype by crossing a selectedvariety (as female) with an inducer variety. Such inducer varieties formaize include Stock 6 (Coe, 1959, Am. Nat. 93:381-382; Sharkar and Coe,1966, Genetics 54:453-464) RWS (see the World Wide Web atuni-hohenheim.de/%7Eipspwww/350b/indexe.html#Project3), KEMS (Deimling,Roeber, and Geiger, 1997, Vortr. Pflanzenzuchtg 38:203-224), or KMS andZMS (Chalyk, Bylich & Chebotar, 1994, MNL 68:47; Chalyk & Chebotar,2000, Plant Breeding 119:363-364), and indeterminate gametophyte (ig)mutation (Kermicle 1969 Science 166:1422-1424), the disclosures of whichare incorporated herein by reference.

Methods for obtaining haploid plants are also disclosed in Kobayashi, M.et al., Journ. of Heredity 71(1):9-14, 1980, Pollacsek, M., Agronomie(Paris) 12(3):247-251,1992; Cho-Un-Haing et al., Journ. of Plant Biol.,1996, 39(3):185-188; Verdoodt, L., et al., February 1998, 96(2):294-300;Genetic Manipulation in Plant Breeding, Proceedings InternationalSymposium Organized by EUCARPIA, Sep. 8-13,1985, Berlin, Germany; Chalyket al., 1994, Maize Genet Coop. Newsletter 68:47; Chalyk, S. T., 1999,Maize Genet. Coop. Newsletter73:53-54; Coe, R. H., 1959, Am. Nat.93:381-382; Deimling, S. et al, 1997, Vortr. Pflanzenzuchtg 38:203-204;Kato, A., 1999, J. Hered. 90:276-280; Lashermes, P. et al., 1988, Theor.Appl. Genet. 76:570-572 and 76:405-410; Tyrnov, V. S. et al., 1984,Dokl. Akad. Nauk. SSSR 276:735-738; Zabirova, E. R. et al., 1996,Kukuruza I Sorgo N4, 17-19; Aman, M. A., 1978, Indian J. Genet PlantBreed 38:452-457; Chalyk S. T., 1994, Euphytica 79:13-18; Chase, S. S.,1952, Agron. J. 44:263-267; Coe, E. H., 1959, Am. Nat. 93:381-382; Coe,E. H., and Sarkar, K. R., 1964 J. Hered. 55:231-233; Greenblatt, I. M.and Bock, M., 1967, J. Hered. 58:9-13; Kato, A., 1990, Maize Genet.Coop. Newsletter 65:109-110; Kato, A., 1997, Sex. Plant Reprod.10:96-100; Nanda, D. K. and Chase, S. S., 1966, Crop Sci. 6:213-215;Sarkar, K. R. and Coe, E. H., 1966, Genetics 54:453-464; Sarkar, K. R.and Coe, E. H., 1971, Crop Sci. 11:543-544; Sarkar, K. R. and Sachan J.K. S., 1972, Indian J. Agric. Sci. 42:781-786; Kermicle J. L., 1969,Mehta Yeshwant, M. R., Genetics and Molecular Biology, September 2000,23(3):617-622; Tahir, M. S. et al. Pakistan Journal of Scientific andIndustrial Research, August 2000, 43(4):258-261; Knox, R. E. et al.Plant Breeding, August 2000, 119(4):289-298; U.S. Pat. No. 5,639,951 andU.S. patent application Ser. No. 10/121,200, the disclosures of whichare incorporated herein by reference.

Use of X5K664 in Tissue Culture

This invention is also directed to the use of hybrid maize varietyX5K664 in tissue culture. As used herein, the term “tissue culture”includes plant protoplasts, plant cell tissue culture, culturedmicrospores, plant calli, plant clumps, and the like. As used herein,phrases such as “growing the seed” or “grown from the seed” includeembryo rescue, isolation of cells from seed for use in tissue culture,as well as traditional growing methods.

Duncan, Williams, Zehr, and Widholm, Planta, (1985) 165:322-332 reflectsthat 97% of the plants cultured which produced callus were capable ofplant regeneration. Subsequent experiments with both inbreds and hybridsproduced 91% regenerable callus which produced plants. In a furtherstudy in 1988, Songstad, Duncan & Widholm in Plant Cell Reports (1988),7:262-265 reports several media additions which enhance regenerabilityof callus of two inbred varieties. Other published reports alsoindicated that “nontraditional” tissues are capable of producing somaticembryogenesis and plant regeneration. K. P. Rao, et al., Maize GeneticsCooperation Newsletter, 60:64-65 (1986), refers to somatic embryogenesisfrom glume callus cultures and B. V. Conger, et al., Plant Cell Reports,6:345-347 (1987) indicates somatic embryogenesis from the tissuecultures of maize leaf segments. Thus, it is clear from the literaturethat the state of the art is such that these methods of obtaining plantsare, and were, “conventional” in the sense that they are routinely usedand have a very high rate of success.

Tissue culture of maize, including tassel/anther culture, is describedin U.S. Application 2002/0062506A1 and European Patent Application,Publication EPO160,390, each of which are incorporated herein byreference for this purpose. Maize tissue culture procedures are alsodescribed in Green and Rhodes, “Plant Regeneration in Tissue Culture ofMaize,” Maize for Biological Research (Plant Molecular BiologyAssociation, Charlottesville, Va. 1982, at 367-372) and in Duncan, etal., “The Production of Callus Capable of Plant Regeneration fromImmature Embryos of Numerous Zea Mays Genotypes,” 165 Planta 322-332(1985). Thus, another aspect of this invention is to provide cells whichupon growth and differentiation produce maize plants having the genotypeand/or morphological and physiological characteristics of hybrid maizevariety X5K664.

This invention includes hybrid maize seed of X5K664 and the hybrid maizeplant produced therefrom. The foregoing was set forth by way of exampleand is not intended to limit the scope of the invention.

Industrial Applicability

Maize is used as human food, livestock feed, and as raw material inindustry. The food uses of maize, in addition to human consumption ofmaize kernels, include both products of dry- and wet-milling industries.The principal products of maize dry milling are grits, meal and flour.The maize wet-milling industry can provide maize starch, maize syrups,and dextrose for food use. Maize oil is recovered from maize germ, whichis a by-product of both dry- and wet-milling industries.

Maize, including both grain and non-grain portions of the plant, is alsoused extensively as livestock feed, primarily for beef cattle, dairycattle, hogs, and poultry.

Industrial uses of maize include production of ethanol, maize starch inthe wet-milling industry and maize flour in the dry-milling industry.The industrial applications of maize starch and flour are based onfunctional properties, such as viscosity, film formation, adhesiveproperties, and ability to suspend particles. The maize starch and flourhave application in the paper and textile industries. Other industrialuses include applications in adhesives, building materials, foundrybinders, laundry starches, explosives, oil-well muds, and other miningapplications.

Plant parts other than the grain of maize are also used in industry: forexample, stalks and husks are made into paper and wallboard and cobs areused for fuel and to make charcoal.

The seed of the hybrid maize variety, the plant produced from the seed,a plant produced from crossing of maize hybrid variety X5K664 andvarious parts of the hybrid maize plant and transgenic versions of theforegoing, can be utilized for human food, livestock feed, and as a rawmaterial in industry.

REFERENCES

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DEPOSITS

Applicant(s) have made a deposit of at least 2500 seeds of maize hybridvariety X5K664 and parental maize inbred varieties GE2099919 andGE3992203 with the American Type Culture Collection (ATCC), Manassas,Va. 20110 USA, ATCC Deposit Nos. PTA-9923, PTA-9913 and PTA-9924,respectively. The seeds deposited with the ATCC on Mar. 27, 2009 weretaken from the deposit maintained by Pioneer Hi-Bred International,Inc., 7250 NW 62^(nd) Avenue, Johnston, Iowa 50131-1000 since prior tothe filing date of this application. Access to this deposit will beavailable during the pendency of the application to the Commissioner ofPatents and Trademarks and persons determined by the Commissioner to beentitled thereto upon request. Upon allowance of any claims in theapplication, the Applicant(s) will make available to the public,pursuant to 37 C.F.R. § 1.808, sample(s) of the deposit of at least 2500seeds of hybrid maize X5K664 with the American Type Culture Collection(ATCC), 10801 University Boulevard, Manassas, Va. 20110-2209. Thisdeposit of seed of maize hybrid variety X5K664 and parental maize inbredvarieties GE2099919 and GE3992203 will be maintained in the ATCCdepository, which is a public depository, for a period of 30 years, or 5years after the most recent request, or for the enforceable life of thepatent, whichever is longer, and will be replaced if it becomesnonviable during that period. Additionally, Applicant(s) have satisfiedall the requirements of 37 C.F.R. §§1.801-1.809, including providing anindication of the viability of the sample upon deposit. Applicant(s)have no authority to waive any restrictions imposed by law on thetransfer of biological material or its transportation in commerce.Applicant(s) do not waive any infringement of their rights granted underthis patent or rights applicable to Maize Hybrid Variety X5K664 andparental maize inbred varieties GE2099919 and GE3992203 under the PlantVariety Protection Act (7 USC 2321 et seq.). U.S. Plant VarietyProtection of parental maize inbred varieties GE2099919 and GE3992203has been applied for. Unauthorized seed multiplication prohibited.

Tables

TABLE 1 VARIETY DESCRIPTION INFORMATION X5K664 AVG STDEV N 1. TYPE:(Describe intermediate types in comments section) 1 = Sweet, 2 = Dent, 3= Flint, 4 = Flour, 5 = Pop and 2 6 = Ornamental. Comments: Dent-Flint2. MATURITY: DAYS HEAT UNITS Days H. Units Emergence to 50% of plants insilk 55 1,239 Emergence to 50% of plants in pollen shed 55 1,239 10% to90% pollen shed 1 36 50% Silk to harvest at 25% moisture 3. PLANT: PlantHeight (to tassel tip) (cm) 267.3 23.05 15 Ear Height (to base of topear node) (cm) 95.9 4.50 15 Length of Top Ear Internode (cm) 18.5 1.4115 Average Number of Tillers per Plant 0.0 0.01 3 Average Number of Earsper Stalk 1.1 0.04 3 Anthocyanin of Brace Roots: 1 = Absent, 2 = Faint,3 3 = Moderate, 4 = Dark 4. LEAF: Width of Ear Node Leaf (cm) 9.8 0.7715 Length of Ear Node Leaf (cm) 85.4 3.89 15 Number of Leaves above TopEar 7.2 1.01 15 Leaf Angle: (at anthesis, 2nd leaf above ear to 30.28.83 15 stalk above leaf) (Degrees) * Leaf Color: V. Dark Green Munsell:7.5GY36 Leaf Sheath Pubescence: 1 = none to 9 = like peach fuzz 5 5.TASSEL: Number of Primary Lateral Branches 9.7 1.91 15 Branch Angle fromCentral Spike 37.3 6.23 15 Tassel Length: (from peduncle node to tasseltip), (cm). 62.1 5.49 15 Pollen Shed: 0 = male sterile, 9 = heavy shed7 * Anther Color: Light Red Munsell: 7.5RP48 * Glume Color: PurpleMunsell: 2.5R28 * Bar Glumes (glume bands): 1 = absent, 2 = present 1Peduncle Length: (from top leaf node to lower florets or 26.4 4.26 15branches), (cm) 6a. EAR (Unhusked ear) * Silk color: Light GreenMunsell: 2.5GY86 (3 days after silk emergence) * Fresh husk color: Med.Green Munsell: 5GY68 * Dry husk color: White Munsell: 5Y92 (65 daysafter 50% silking) Ear position at dry husk stage: 1 = upright, 2 =horizontal, 1 3 = pendant Husk Tightness: (1 = very loose, 9 = verytight) 5 Husk Extension (at harvest): 1 = short(ears exposed), 2 2 =medium (<8 cm), 3 = long (8-10 cm), 4 = v. long (>10 cm) 6b. EAR (Huskedear data) Ear Length (cm): 18.9 1.25 15 Ear Diameter at mid-point (mm)44.5 1.51 15 Ear Weight (gm): 199.0 26.93 15 Number of Kernel Rows: 15.31.23 15 Kernel Rows: 1 = indistinct, 2 = distinct 2 Row Alignment: 1 =straight, 2 = slightly curved, 3 = spiral 2 Shank Length (cm): 9.7 1.8315 Ear Taper: 1 = slight cylind., 2 = average, 3 = extreme conic. 2 7.KERNEL (Dried): Kernel Length (mm): 12.6 0.63 15 Kernel Width (mm): 7.90.52 15 Kernel Thickness (mm): 4.1 0.26 15 Round Kernels (shape grade)(%) 11.3 2.69 3 Aleurone Color Pattern: 1 = homozygous, 2 = segregating1 * Aleurone Color: Yellow Munsell: 10YR814 * Hard Endo. Color: YellowMunsell: 10YR714 Endosperm Type: 3 1 = sweet (su1), 2 = extra sweet(sh2), 3 = normal starch, 4 = high amylose starch, 5 = waxy starch, 6 =high protein, 7 = high lysine, 8 = super sweet (se), 9 = high oil, 10 =other Weight per 100 Kernels (unsized sample) (gm) 27.3 2.08 3 8. COB: *Cob Diameter at mid-point (mm): 21.8 0.56 15 * Cob Color: Pink OrangeMunsell: 10R68 10. DISEASE RESISTANCE: (Rate from 1 = most-susceptableto 9 = most-resistant. Leave blank if not tested, leave race or strainoptions blank if polygenic.) A. LEAF BLIGHTS, WILTS, AND LOCAL INFECTIONDISEASES Anthracnose Leaf Blight (Colletotrichum graminicola) CommonRust (Puccinia sorghi) Common Smut (Ustilago maydis) Eyespot (Kabatiellazeae) Goss's Wilt (Clavibacter michiganense spp.  5 Gray Leaf Spot(Cercospora zeae-maydis) Helminthosporium Leaf Spot (Bipolaris zeicola)Race:  5 Northern Leaf Blight (Exserohilum turcicum) Race: Southern LeafBlight (Bipolaris maydis) Race: Southern Rust (Puccinia polysora)  6Stewart's Wilt (Erwinia stewartii) Other(Specify):                                                 B. SYSTEMICDISEASES Corn Lethal Necrosis (MCMV and MDMV)  2 Head Smut(Sphacelotheca reiliana) (% infected) Maize Chlorotic Dwarf Virus (MDV)Maize Chlorotic Mottle Virus (MCMV) Maize Dwarf Mosaic Virus (MDMV)Sorghum Downy Mildew of Corn (Peronosclerospora sorghi) Other(Specify):                                                 C. STALK ROTS 4 Anthracnose Stalk Rot (Colletotrichum graminicola) Diplodia Stalk Rot(Stenocarpella maydis) Fusarium Stalk Rot (Fusarium moniliforme)Gibberella Stalk Rot (Gibberella zeae) Other (Specify): D. EAR ANDKERNEL ROTS Aspergillus Ear and Kernel Rot (Aspergillus flavus)  6Diplodia Ear Rot (Stenocarpella maydis)  6 Fusarium Ear and Kernel Rot(Fusarium moniliforme) Gibberella Ear Rot (Gibberella zeae) Other(Specify):                                                 11. INSECTRESISTANCE: (Rate from 1 = most-suscept. to 9 = most-resist., leaveblank if not tested.) Corn Worm (Helicoverpa zea)     Leaf Feeding    Silk Feeding     Ear Damage Corn Leaf Aphid (Rophalosiphum maydis)Corn Sap Beetle (Capophilus dimidiatus) European Corn Borer (Ostrinianubilalis) 1st. Generation (Typically whorl leaf feeding) 2nd.Generation (Typically leaf sheath-collar feeding)     Stalk Tunneling    cm tunneled/plant Fall armyworm (Spodoptera fruqiperda)      LeafFeeding      Silk Feeding      mg larval wt. Maize Weevil (Sitophiluszeamaize) Northern Rootworm (Diabrotica barberi) Southern Rootworm(Diabrotica undecimpunctata) Southwestern Corn Borer (Diatreaeagrandiosella)      Leaf Feeding      Stalk Tunneling      cmtunneled/plant Two-spotted Spider Mite (Tetranychus utricae) WesternRootworm (Diabrotica virgifrea virgifrea) Other(Specify):                                                 12. AGRONOMICTRAITS:  4 Staygreen (at 65 days after anthesis; rate from 1-worst to9-excellent) % Dropped Ears (at 65 days after anthesis) % Pre-anthesisBrittle Snapping  4 % Pre-anthesis Root Lodging 13 % Post-anthesis RootLodging (at 65 days after anthesis) 18 % Post-anthesis Stalk Lodging12,282.0 Kg/ha (Yield at 12-13% grain moisture) * Munsell Glossy Book ofColor, (A standard color reference). Kollmorgen Inst. Corp. New Windsor,NY.

TABLE-2A HYBRID COMPARISON Variety #1: X5K664 Variety #2: 35D28 YIELDGLFSPT YIELD NLFBLT SLFBLT MST BU/A 56# SCORE BU/A 56# SCORE SCORE PCTStat ABS ABS % MN ABS ABS ABS Mean1 195.7 4.8 102.2 4.8 3.0 18.9 Mean2187.0 4.8 98.0 5.3 3.0 19.0 Locs 151 12 151 12 1 151 Reps 192 19 192 201 192 Diff 8.7 0.0 4.2 −0.5 0.0 0.2 Prob 0.000 0.945 0.000 0.194 — 0.098TSTWT STWWLT ANTROT EGRWTH FUSERS ESTCNT LB/BU SCORE SCORE SCORE SCORECOUNT Stat ABS ABS ABS ABS ABS ABS Mean1 57.4 5.4 4.5 5.8 6.5 53.4 Mean255.6 4.9 3.8 5.1 3.2 49.9 Locs 117 4 6 9 6 9 Reps 145 6 12 10 16 12 Diff1.8 0.4 0.7 0.7 3.2 3.6 Prob 0.000 0.310 0.418 0.109 0.001 0.084 GIBERSSTKCNT DIPERS GDUSHD GDUSLK PLTHT SCORE COUNT SCORE GDU GDU CM Stat ABSABS ABS ABS ABS ABS Mean1 6.5 53.8 6.6 131.3 131.6 314.8 Mean2 6.9 53.45.9 134.5 135.0 321.9 Locs 2 221 8 30 30 50 Reps 4 356 16 42 38 68 Diff−0.4 0.4 0.6 −3.2 −3.3 −7.1 Prob 0.205 0.039 0.239 0.000 0.000 0.002SOURST EARHT STAGRN GIBROT HDSMT STLLPN SCORE CM SCORE SCORE % NOT % NOTStat ABS ABS ABS ABS ABS ABS Mean1 3.0 126.0 4.0 7.8 98.5 82.6 Mean2 3.0133.2 3.1 5.0 97.6 70.5 Locs 1 49 42 3 8 28 Reps 1 66 54 6 14 58 Diff0.0 −7.2 0.9 2.8 0.9 12.1 Prob — 0.000 0.000 0.051 0.127 0.007 STLPCNERTLPN ECBLSI LRTLPN BRTSTK HSKCVR % NOT % NOT SCORE % NOT % NOT SCOREStat ABS ABS ABS ABS ABS ABS Mean1 82.0 96.3 5.6 86.3 72.7 5.9 Mean270.3 90.9 4.0 80.3 96.0 4.7 Locs 26 6 10 29 10 14 Reps 32 9 12 42 16 15Diff 11.8 5.4 1.6 6.1 −23.4 1.2 Prob 0.016 0.195 0.009 0.297 0.009 0.005

TABLE-2B HYBRID COMPARISON Variety #1: X5K664 Variety #2: 35Y33 YIELDGLFSPT YIELD NLFBLT SLFBLT MST BU/A 56# SCORE BU/A 56# SCORE SCORE PCTStat ABS ABS % MN ABS ABS ABS Mean1 193.5 4.8 102.5 4.8 3.0 18.9 Mean2184.2 4.6 98.3 6.8 3.5 19.9 Locs 124 11 124 9 1 124 Reps 141 18 141 13 2141 Diff 9.3 0.3 4.1 −2.1 −0.5 1.0 Prob 0.000 0.137 0.001 0.003 — 0.000TSTWT STWWLT ANTROT EGRWTH FUSERS ESTCNT LB/BU\ SCORE SCORE SCORE SCORECOUNT Stat ABS ABS ABS ABS ABS ABS Mean1 57.3 5.4 4.5 6.0 6.4 58.1 Mean257.7 5.9 5.4 6.0 4.8 56.4 Locs 102 4 6 8 5 8 Reps 116 6 12 8 12 10 Diff−0.4 −0.6 −0.9 0.0 1.6 1.8 Prob 0.001 0.633 0.424 1.000 0.061 0.433GIBERS STKCNT DIPERS GDUSHD GDUSLK PLTHT SCORE COUNT SCORE GDU GDU CMStat ABS ABS ABS ABS ABS ABS Mean1 6.5 54.1 6.6 131.4 131.7 312.6 Mean25.6 54.0 4.8 130.5 129.6 303.9 Locs 2 188 8 24 28 41 Reps 4 273 16 30 3451 Diff 0.9 0.1 1.8 0.9 2.1 8.7 Prob 0.722 0.666 0.035 0.106 0.001 0.000SOURST EARHT STAGRN GIBROT HDSMT STLLPN SCORE CM SCORE SCORE % NOT % NOTStat ABS ABS ABS ABS ABS ABS Mean1 3.0 124.1 4.3 7.8 98.5 84.6 Mean2 3.0119.9 4.6 8.4 94.7 86.4 Locs 1 41 32 3 8 23 Reps 1 51 34 6 14 44 Diff0.0 4.2 −0.4 −0.6 3.7 −1.8 Prob — 0.037 0.104 0.562 0.007 0.651 STLPCNERTLPN ECBLSI LRTLPN BRTSTK HSKCVR % NOT % NOT SCORE % NOT % NOT SCOREStat ABS ABS ABS ABS ABS ABS Mean1 85.9 96.0 5.6 81.5 65.8 5.9 Mean293.5 81.5 5.6 78.3 94.4 5.8 Locs 20 5 8 20 8 14 Reps 20 7 8 24 10 15Diff −7.7 14.5 0.0 3.2 −28.6 0.1 Prob 0.221 0.432 1.000 0.633 0.0130.752

All publications, patents and patent applications mentioned in thespecification are indicative of the level of those skilled in the art towhich this invention pertains. All such publications, patents and patentapplications are incorporated by reference herein for the purpose citedto the same extent as if each was specifically and individuallyindicated to be incorporated by reference herein.

The foregoing invention has been described in detail by way ofillustration and example for purposes of clarity and understanding. Asis readily apparent to one skilled in the art, the foregoing are onlysome of the methods and compositions that illustrate the embodiments ofthe foregoing invention. It will be apparent to those of ordinary skillin the art that variations, changes, modifications and alterations maybe applied to the compositions and/or methods described herein withoutdeparting from the true spirit, concept and scope of the invention.

1. A maize hybrid variety X5K664, representative seed of said varietyhaving been deposited under ATCC Accession Number PTA-9923.
 2. A seed ofthe maize hybrid variety of claim
 1. 3. A plant of the maize hybridvariety of claim
 1. 4. A plant part of the maize hybrid variety ofclaim
 1. 5. Pollen of the plant of claim
 3. 6. An ovule or ovules of theplant of claim
 3. 7. A seed according to claim 2, wherein said seedcomprises a mutant or transgenic gene that confers a characteristicselected from the group consisting of herbicide resistance, insectresistance and disease resistance.
 8. A plant according to claim 3,wherein said plant comprises a mutant or transgenic gene that confers acharacteristic selected from the group consisting of herbicideresistance, insect resistance and disease resistance.
 9. A maize plant,or a part thereof, having all the morphological and physiologicalcharacteristics of the maize hybrid variety X5K664, representative seedof said variety having been deposited under ATCC Accession NumberPTA-9923.
 10. A process for producing a maize seed, comprising crossingthe plant of claim 3 with itself or a different maize plant andharvesting the resultant maize seed.
 11. The process of claim 10,wherein said different maize plant is a haploid inducer.
 12. An F1hybrid maize seed produced by crossing the plant of claim 3 with adifferent maize plant and harvesting the F1 hybrid maize seed.
 13. Amaize plant produced by growing the F1 hybrid maize seed of claim 12.14. A process of introducing a desired trait into a maize hybrid varietyX5K664 comprising: (a) crossing at least one of maize inbred varietyparent plants GE2099919 and GE3992203, representative seed of which havebeen deposited under ATCC Accession Number(s) as PTA-9913 and PTA-9924respectively, with plants of another maize variety that comprise adesired trait to produce F1 progeny plants, wherein the desired trait isselected from the group consisting of male sterility, site-specificrecombination, increased transformability, abiotic stress tolerance,herbicide resistance, insect resistance, resistance to bacterial,fungal, nematode or viral disease, altered phosphorus, alteredantioxidants, altered fatty acids, altered essential amino acids andaltered carbohydrates; (b) selecting said F1 progeny plants that havethe desired trait to produce selected F1 progeny plants; (c)backcrossing the selected progeny plants with said maize inbred varietyparent plant to produce backcross progeny plants; (d) selecting forbackcross progeny plants that comprise the desired trait and themorphological and physiological characteristics of said maize inbredvariety parent plant to produce selected backcross progeny plants; (e)repeating steps (c) and (d) for at least three additional generations toproduce at least a first progeny plant, wherein said first progeny plantcomprises the desired trait; (f) crossing the progeny plant of step (e)with a plant of the other maize inbred variety of the group consistingof variety GE2099919 and GE3992203 to produce a seed that produces aconverted plant of maize hybrid variety X5K664, where the convertedplant of variety X5K664 comprises the desired trait and all of themorphological and physiological characteristics of maize hybrid varietyX5K664 listed in Table 1 as determined at the 5% significance level whengrown in the same environmental conditions.
 15. A plant produced by themethod of claim 14, wherein the plant has the desired trait and all ofthe morphological and physiological characteristics of maize hybridvariety X5K664 listed in Table 1 as determined at the 5% significancelevel when grown in the same environmental conditions.
 16. The plant ofclaim 15, wherein the desired trait is male sterility and the trait isconferred by a nucleic acid molecule that confers male sterility. 17.The plant of claim 15, wherein the desired trait is site-specificrecombination and the site-specific recombination is conferred by amember of the group consisting of flp/frt, cre/lox, Gin, Pin, and R/RS.18. The plant of claim 15, wherein the desired trait is herbicideresistance and said herbicide is glyphosate, glufosinate, a sulfonylureaherbicide, an imidazolinone herbicide, a hydroxyphenylpyruvatedioxygenase inhibitor or a protoporphyrinogen oxidase inhibitor.
 19. Theplant of claim 15, wherein the desired trait is insect resistance andsaid insect resistance is conferred by a nucleic acid molecule encodinga Bacillus thuringiensis endotoxin.
 20. The plant of claim 15, whereinthe desired trait is fungal resistance and the disease is caused byColletotrichum.
 21. The plant of claim 15, wherein the desired trait isaltered carbohydrate and the carbohydrate is waxy starch.